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Why does PTC company not to develop a suitable gear system?

bduncan
15-Moonstone

Why does PTC company not to develop a suitable gear system?

Why does PTC company not to develop a suitable gear system? We just only need to enter the appropriate data that can generate a 3-D gear models, in this way to enhance efficiency. I know there is such a system for SW or gear plug-in( called GearTrax). Inventor also has such a system

18 REPLIES 18
JoshH
3-Visitor
(To:bduncan)

There are plenty of possible answers, although I would expect that what will come down to is "bang for the buck".

Gears can be developed in Pro/E, but it does take knowledge of gear design. Once you get one done, you can spit out variations really easily. That being said, if you're not hobbing your own gears, you're probably buying them from someone that does and has their own gear design software.

So ultimately, I would say that there are probably more projects within PTC (such as Lightening) that they see as much more valuable and worthy of allocating time to than a functionality that is not going to get them any new contracts or close a glaring gap in their software.

That being said, I'd be real interested in seeing the involute derivation from SW or Autodesk. I have seen several PTC models that do this fairly accurately.

It would be a 'nice-to-have', but even working for a transmission company it's not really essential. Since gears are manufacturing by hobbing (or shaping, or grinding) on gear manufacturing machines, there's usually no requirement to model the involute accurately - a sketch using a couple of arcs is sufficient to make gears 'look right' on a drawing. It's very unusual to cut gears directly from CAD.

If accurate gears are required, it's fairly simple to use an equation-driven curve to produce the profile - you just need the equation for an involute, and enough parameters to define the gear (I think base circle, root and tip diameter, and number of teeth are sufficient).

Yes, but I want my models are three dimensional, and easy to check for interference, motion simulation, etc., With other people's ideas, isn't it? this is also more straightforward.

Check this out. It is in german but might still be useful -> http://userserv.fh-reutlingen.de/~wyndorps/Deutsch/ProE.htm

Thank you for the link. I still hope that PTC company be able to develop a complete gear system, so we work even more easily.

Intersting site. Do you know of any english language versions?

I wish they had one too, many companies need to design custom gear trains. From personal experience, there is a lot more to getting a gear train to perform in real life than you learn in school. I'm guessing that's why some folks make statements along the lines that it isn't really necessary to have a geometrically accurate gear model. But gears are not as simple as commodity items like deep groove bearings because they interact with one another and getting the interaction the way you need it to be is not simple at all. Like any other assembly, having a dimensionally accurate model is an aid to the gear train design process for those of us who are really designing them as opposed to making simple drawings and leaving the details to others who are skilled in the art. If that level of play was acceptable I would be working at a drafting table and not on a "leading" CAD platform. As it is now, it takes a lot of time for you to create a gear model in Pro/E from scratch, let alone one with accurate geometry that deals properly with undercuts, profile shifts, clearances. I can't think of too many people who have the time to make such a model when they have to budget their time to develop a whole machine, not just a gear. Inventor and Solid Works both have nice gear design modules but PTC leaves us hanging. I hope they will offer something competitive, but the only way I see PTC coming out with such a program is if the can sell it for 5K as an optional module.

Best of luck!

Walt

"having a dimensionally accurate model is an aid to the gear train design process for those of us who are really designing them as opposed to making simple drawings and leaving the details to others"

To clarify a little, the reason we can get away with pictorial models is that we do our gear design (and shaft/bearing analysis) in our own in-house software (Ricardo SABR - which is also commercially available... </plug> ). This deals with tooling, undercut, contact ratio, bending stress and life, contact stress and life, backlash and all the rest of it... Somehow, a 3D modelling package doesn't really seem like the right tool - it's too specialised an area. Also, the parameters can be defined mathematically, without needing to see the whole thing in 3D - I don't see that it's really a 3D problem as there are only a limited number of degrees of freedom, unlike designing a casting which can take an unlimited variety of different forms.

Now, if Pro/E could generate cuts by sweeping a volume, this would not only give an easy way to produce accurate gears - by simulating the hobbing process - but would be useful for a lot of milled features too.

gvora
6-Contributor
(To:bduncan)

Hello Blue,

I have requested the same thing to PTC by the product enhancement for more than a year.

There is no update from PTC side.

Thanks.

Gautam Vora.

bduncan
15-Moonstone
(To:gvora)

PTC goes it's own way.

gvora
6-Contributor
(To:bduncan)

I thank you for your reply.

Gautam Vora.

s.iyer
1-Newbie
(To:bduncan)

For any kinematic analysis, one need not model a gear unless the same is going to be manufactured by RPT process. For any other parameter like undercut, contact ratio and such other parameters, one can always input formulae in an Excel sheet. Undercut is a function of Pressure angle and minumum number of teeth, while contact ratio is a function of proportion of "Addendum" and "Dedundum" for S0 and S1 corrected gears or for that matter Helical gears. All of these are mathematical functions / derivations. One can still define an equation for an involute (the base circle dia remains the same irrespective of gear correction), or perhaps drive the model parameters from the Excel table. This is a possibility. Though I never bothered to model a gear (A surface representing the OD is good enough for my applications), I had read certain forum postings detailing a method to drive the Proe parameters from an Excel table.

One might also consider a UDF feature.

there is no need to relie on plug-ins. Pro/E itself capable of genrating Gear systems only if hv good knowldege of gears design calculations.

gvora
6-Contributor
(To:bduncan)

I HAVE REQUESTED THAT AS PRODUCT ENCHANCEMENT TO PTC.

VladimirN
24-Ruby II
(To:gvora)

bduncan
15-Moonstone
(To:gvora)

Thank you! I hope we can see the gear system will be integrated in the future creo version.maybe creo 4.0

dschenken
21-Topaz I
(To:bduncan)

Search for Gearotic to find a simple gear design system.

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