Spline Dimensions...

[[Mi...]]

I'm trying to wrap my head around some of these measurements...

We do not have gear pro, curve or freeform.

Most of them are fine, but the Circular Tooth thicknesses, MAX EFFECTIVE, and MIN EFFECTIVE I'm not following.

My counterpart has a way of doing this, but the current program has 261 secondary alignments, and there's no way I could replicate what is done. It also took 3 days.

To do the over pins I scanned 2d lines on each tooth side and then just put 6.25mm tangent circles in each space, then used caliper distance.

Can anybody explain in a dumbed down way what MAX EFFECTIVE and MIN EFFECTIVE actually are... and hopefully a fairly simple way to do them.

I see there's a circular pitch characteristic available that sounds like it's going to be helpful.

Spline Data.PNG

[[Jo...]]

I usually deal with involute splines and don't know what max effective and min effective are. (Tolerance Zone maybe)??
However, I scan both side of the tooth and create a theoretical pitch diameter and intersect each side of the tooth for a distance.

[[Mi...]]

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Yup, that's exactly what I did too, there doesn't seem to be a way of actually getting the Arc length directly so I did with a formula using a result element.

the effective callouts are puzzling... and I'm pretty sure without GearPro we can't report them 100% correctly, but hoping for a good enough approach that doesn't take multiple days.

[[Ji...]]

Michael,

All of these dimensions can be done trivially with GearPro. I would also bet folding money that the 261 alignment method is not giving you the ideal answer.

First, 2dlines on an involute face will be unable to really consider any effective value, as Calypso will always use the calculated feature. An involute is inherently a curve and the tooth thickness is considered at the roll diameter location through the involute shape. The diameter in question is usually the pitch circle, but there are other selections that could work depending on your requirements. Over balls values and tooth thickness, while related, are not the same. The simulated pin, even using the involute curve, can only really consider the tooth spacing and related values.

Maybe you should come and visit us and we can re-check a part so you can see whether your current methods are valid?

[[Ch...]]

Hello ..


Gear + Spline guy here ...

This is a fairly standard spline, however I can't imagine trying to inspect it all as you mentioned in Calypso, let alone without curve /FF, etc.

(Just noticed this is a 50° spline, a bit unusual, typical is 30° pressure angle, next common is 45° (also known as serrations).)

However, it may still able to be done, as Gear Pro is essentially a macro wrapper for calypso movements/measurements, etc.

Regarding "Effective" CTT/CSW : here's some more info : https://gearsolutions.com/features/actu ... ooth-size/
It basically account for a min/max mating part and some pitch/lead/profile errors. Notice min eff, max actual are REF, this is typically what gages are made to, Opposite for external.

I don't see a spec listed, however ANSI B92.1 mostly states splines are acceptable to properly made gages. However, from a quality stand point, it is good to check some things analytically. If you have no gages available, then you must inspect analytically, Fp, Fa, Fß, (+ probably Fr).

If you find a spec, and a spline class, we can help you further. Assuming this is ANSI B92.1, if no class is specified this would be Class 5. In which case you could theoretically inspect lead and pitch, however because the profile tolerance is a bit wonky, I prefer not to go into depth about it, you will not be able to measure/report the involute profile accurately.

I just noticed, this requires 'flat pins' to inspect the over ball/pin sizes, this may be an issue with the tangent construction.

Kudos to you for trying, I have done similar in Calypso when needed as well, however I think the proper way to do this is spline Go/No-Go gages or analytical with Gear Pro or Gear analyzer.

I would only report actual C.T.T, disregard 'effective'. Actual CTT is also typically calculated from the M.O.P.'s There are some free calculators online. (If you have a flatted pin set and can get a reading, etc.)

Also as a note, Form diameter is typically a basic dimension as well, it is really where the involute begins and id verified with a profile measurement. It is where a largest mating gear would contact.

Good luck

[[Mi...]]

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Thanks for all the info!

I definitely need to learn more about gears, trying to sell management on GearPro. We have so many parts with a gear in one form or another.

[[Ke...]]

Ususally I'm only requested to do over/between pin, min &max diameters; and, for the most, part I am able to use standard probe sizes, for the over/between pin measurements... but, I was recently presented with an example that is perfect for GearPro. The catch is that my training was about 3 years ago, and I have forgotten mostly everything. Before I go digging into the GearPro portion of the forum: does anyone have any maretials or links to "how to" videos?

[[Je...]]

.

I hope your sales engineers quoted a generous amount of programming time for CMM 😕

If your company takes on this type of project regularly, it may be an opportunity to ask either your customer or your manager to upgrade to curve/freeform/Gearpro.

Hang in there. When not getting crunched on delivery time, I really enjoy these types of challenging projects.


Jeff Frodermann
Meier Tool & Engineering
Anoka, Minnesota

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[[Ow...]]

See attached.
At least half of what I know about gears and splines I learned from this guy.

Actual_vs._Effective_Involute_Tooth_Spline_Size.pdf