Dimension measuring over wires on Gear 2

[SeasonLee]

Our manufacturer claimed that something wrong on the print data, they can’t meet the dimension over the wires, I am trying to find out the correct dimension over wires (pins) from the internet calculator, but I got different answers from them (pls ref to page 2 / 3 on the attached):

1st calculator---

http://www.zakgear.com/Over_Pins.html

2nd calculator---

http://www.salemcompany.com/cgi-bin/Store/commerce.cgi?page=InvSpanPinC.html&cart_id=1347556998.192

Anything wrong on my calculator key-in? What is the correct dimension over wires?

Thanks for all of your assists

SeasonLee

 

[mfgenggear]

Seasonlee
what is the circular tooth thickness required?
please advise

Mfgenggear

 

[SeasonLee]

Thanks for your reply, Mfgenggear.

Attached print is all we have, are there any ways to calculate the tooth thickness from existing print?
Thanks

Richard Lee

 

[mfgenggear]

Richard

CTT calcs to .0618693/.0603660
No problem with your print far as mfg.
find attach spread sheet.
what is your suppliers complaint

Mfgenggear

 

[SeasonLee]

Excellent, Mfgenggear.

They mentioned that if they meet the dimension over wires, the major diameter will become smaller to 3.334, I am trying to confirm what they said is correct or not.

May I ask what calculator you are using?

Thanks

Richard Lee

 

[mfgenggear]

Seasonlee

I wrote my own program, on excel.I been using it for 17 years for our required mfg.
Broach Masters & Ash gear sells a good program.

It may Top the major diameter with standard D+F .112 Hob.
If it's a good qty, a special ordered hob can be order from American Tools,Gleason Cutting Tools or from Koepfer.
& it will not top the major dia., I do it often.

Mfgenggear

 

[SeasonLee]

Thanks again, Mfgenggear.

Richard Lee

 

[israelkk]

mfgenggear

Did you calculated the tooth thickness based on the MOW in the drawing or you received the MOW based on the gear parameter?

When you use the gear parameter the MOW is much larger (over 3.42). I have used my own program, Commercial program and one more manufacturer program and they all give larger MOW.

The gear is not correctly defined. AGMA 6 is not a clear definition because it is not clear if it is AGMA 390.01, 390.02, 390.03, AGMA 2000-A88, etc.

Did you account for the Total Composite Tolerance and Tooth thickness tolerance and Tooth reduction (for minimum backlash) of AGMA 6 and how they affect the minimum and maximum MOW?

Did you account for the profile modification in the drawing when you calculated the MOW?

I am quite sure the run out of 0.002 on the MOW is not comparable with AGMA 6 (much smaller than the TCT.

 

[SeasonLee]

israelkk

Would you mind pinpoint which item (or data) is not correctly defined, and the correct MOW.
Thanks for your comments

SeasonLee

 

[israelkk]

I think my post is clear to whom has some knowledge of gear dimensioning and it includes what is not correctly defined. The first is to clearly define the designer intention for the AGMA version. Is this a new or old drawing?

 

[mfgenggear]

israelkk

First off let me advise I have the most of respect for you.

I have done Gear Manufacturing for 40 Years, & it is not uncommon for Engineers to draw as the gear data as shown.
my take on this, is this gear manufacturable & the answer is yes.
what is the fit form or function, unknown.
Does it need improvement probably
I do not like getting into wars here because there is more than one way to make parts.
just as I had the discussing about Span Measurement versus M.O.W in the past.


but it is common to give the MOW with out Making it Inclusive with the TCE, Involute, Lead.
It is an option of the designer & what he or she specifies.
It is optional to give separate analytical verifications with Pitch Variation, Lead & Involute.
The rational: Most gear manufacture are now using CNC Gear Inspection Equipment. & Master Gears are not as common as it use to be.
I know an Inclusive verification with Master Gears is a very viable tool and if that is what the designer specifies then that is what needs to be done. No Argument.
But it can be optional either way.

With Case Hardening Gears , IE: Carburize , Nitrided, It is preferable that the M.O.W not be inclusive of all of the Analytical Attributes.
because the manufacture has to allow for pre grind data. & then finish grind post heat treat. This makes it easy clean for me so that it is easy to calculate. That is my preference, and 99% of my customers do it this way in the states.

As far as the AGMA quality, your question about that is correct, it should be clarified between customer & supplier.
If I was processing this job I would have ask for clarification. However that said I have read in AGMA spec's clarification on how to specify the AGMA quality class, as follows,
I am not at my office so I do not have my ref material with me.
But it is some what like this
AGMA 6 = if the Q is not specified it falls under the AGMA 390
AGMA Q 6 = if the Q is specified it falls under AGMA 2000
and so on on

So final analysis : It depends on the designer and the fit form & function of the Parts.

Take Care

Mfgenggear

 

[SeasonLee]

Thanks, israelkk.

The drawing created at 2010. If the designer intention is AGMA class 6, would you please let me know which data is not properly defined, sorry for the easy question since I am not a designer.

SeasonLee

 

[dinjin]

It might be of interest in understanding the profile shift of the ring gear to know more about the pinion. It may simply be a long and short addendum system to avoid undercutting in the root of the pinion. Just curious. The wire or pin size was suspect so I assume they are using 2.2mm pins. Thanks to Mfgenggear for writing his own program. That is the best way to understand all of the parameters in the calculations.

 

[SeasonLee]

Our manufacturer found out where is the problem on the gear hobbing based on the spread sheet provided by Mfgenggear, thanks for all of your assists.

SeasonLee