Help! New Engineer Need help identifying CV shaft spline standard 9

[Speedracerfast]

Hi everyone,

My first post here. I am a young engineer and just got my first job out of college as a design/reverse engineer for a aerospace company. Currently I am doing my own automotive projects on the side and having trouble identifying this spline. Long story short, I am retrofitting tapered roller bearings into a hub and spindle for a old Isuzu. I have virtually everything complete besides matching this spline standard. I've been beating my head on this part for a bit now, and would appreciate any insight. Also I can't find a copy of any JIS spline standards that don't cost upwards of +$350!

Pics attached too.

I am pretty sure it is JIS-D-2001 or JIS 1603 B. Although it is probably a JIS-D-2001 because its a cv shaft, meaning major diameter fit. I could be wrong about it being a JIS standard because my research points out that GM had a lot to do with building this car.

Spec/Dimensions I've found below via optical comparator:

Internal Spline
24 Teeth
Small ID (tip to tip): 0.975"
Big ID (root to root): 1.06"
Tip width : 0.027"
Root Width : 0.017"
Angle of tooth (paint drawing attached for clarification): 40-50 degrees

 

[Speedracerfast]

THANK YOU!!!!!!!!!!!

 

[Speedracerfast]

mfgenggear that pdf you shared only has it for 36 or 48 teeth, or "serrations" as they call it. Am I missing something here?

 

[mfgenggear]

nope sorry about that but the formula applies just the # of teeth, stick with the asme b92.1

 

[Speedracerfast]

Hi everyone,

So I think I'll go with a Mylar sheet drawing and pay for that service. However I can't seem to find a trustworthy/ legit website to convert my involute spline geometry to dxf file. I've started to model it in Solidworks but not sure it'll come out right. Would love to check my work.

 

[gearguru]

How are you modeling it? Do you have the points on the involute flanks calculated?
Years ago I created an OpenOffice spreadsheet for a friend to do just that. He then used the calculated coordinates to create a "script" (in DraftSight) to draw the curves and completed the tooth geometry (root, tip arc) "manually" and used it in wirecutting the gear.
I don't have access to any CAD anymore, but I think that Solidworks has some scripting or user's programming tool too.

 

[lfw618]

If you're using Solidworks, you can model the involute curve with a parametric equation driven curve. x=BR*(cos(t)+t(sin(t)) y=BR*(sin(t)-tcos(t)), then mirror that around a line to .5 of your circular space width to get your spline tooth.

 

[spigor]

Do you want a dxf file with that spline from us? You suggested you had access to an optical comparator at work even though it is your personal project- why didn't you tell us if my sketch matches the actual part? Assuming it does, do you want a dxf file of:
a) an involute spline calculated from your second measurements, i.e. of my sketch,
b) an involute spline corrected to standard B92.1 with loose fit as indicated by your measurements, possibly resulting from wear, or
c) an involute spline as per B92.1 Class 5, tighter, but you can always run another WEDM cut if it's too tight?

 

[Speedracerfast]

spigor: If you could do a, b, and c that would be awesome! I'd owe you a steak dinner haha. I haven't sent your original file out for printing yet because I want all three. Also keep in mind I have limited access with work machines for personal projects; don't want to stretch these freedoms and get fired.

lfw618: cool thank you! I will give this a shot this weekend.

gearguru: I have two angles posted above, and root diameter and tip diameter. Isn't this enough to full define it? I know my #'s are accurate about .0045" differences max when comparing them to comparator and vision system. Again I took three measurements per machine and took average.

If I can model them like I described above, convert it to dxf on solidworks, and then and pop in spigor's dxf file, that would be another way to compare, yea?

Again thanks for all the help everyone! Learned so much through this process.

 

[gearguru]

I used the following data to model the tooth geometry:

module or diametral pitch
# of teeth
pressure angle at pitch dia
tooth thickness at pitch dia (which is measured as arc length)
major dia
minor dia

Then you will also need to model the root geometry so that it does not interfere with the internal spline.
(Be aware that those tooth thicknesses in posts above are measured/calculated as the arc lengths - portion of the pitch circle which runs between the two flanks!)

I trust spigor, he knows what he is doing.

 

[mfgenggear]

hope this helps

https://geargenerator.com/#200,200,...0,0,0,0,0,13,3.25,4,27,-90,0,0,0,0,0,1,3,1553

 

[mfgenggear]

also if you believe the data is correct I can also create the DXF file
perfect for EDM

 

[spigor]

@gearguru
Thank you

Speedracerfast, Speedracerfast
Here is a dxf file with an involute spline profile calculated from your initial measurements, and it also contains a spline profile based on your second measurements corrected to standard B92.1 Class 5 (pink):

https://files.engineering.com/getfi...40-8ae82892b642&file=1st_try_and_the_last.DXF

The fillet should WEDM ok, but if not you need to decrease the major diameter and therefore to increase the fillet radius.
Here is also a pdf version for reference:

https://files.engineering.com/getfi...6a1-4cee-982d-2d99b7f002f4&file=MegaPlot2.pdf

 

[gearguru]

Well, mfgenggear is a very reliable source and "old" and knowledgeable member of this site too.
Actually everybody in this thread brought interesting and valuable input.

@mfgenggear : Thanks for the interesting links. The geargenerator web is nicely done, but does not allow to enter the tooth thicknesses and does not create the internal gears. Therefore before the dxf file created there is used, has to be properly edited. If the involutes created there are properly calculated is a question too, we do not know the calculation methods used there. It is also interesting, that the inch based system (DP, not the metric, module) is used there - that site was obviously created in the Europe.

 

[gearguru]

I played with the geargenerator again. There is the option to create the internal gears as well. (in gear properties click on the box "internal". I was wrong in my previous entry.
Very clever program. Now I'll check if I can enter my own major and minor diameters...

 

[mfgenggear]

Hi @gearguru
Yes the site needed vetting.
For accuracy.i can not take credit for
Online gear generator. It belongs to some one else.

I can create dxf files that are very accurate. I had parts were wire Cut gears and splines and we're verify with CNC gear checker to be with in .0004 involute tolerance.

Also let me reciprocate the thanks.
I have learned so much from other posters as well
I try to verify any calculations or programs with each other. Correct calculations should agree with the same results. I like using old dos programs that have worked well over the years plus I have written my own and vetted them as accurate.
By testing and verifing my results.

Just as my days working in the shop.
Measure 3 times, then cut.

 

[gearguru]

@mfgeggear: I sent an email to the owner of the geargenerator, I believe he is in Hungary. Obviously he is a very skilled programmer.
My calculations are mostly done in a spreadsheet, but in the past I also tried to create some simple programs in VB. They still work. Now I am retired and only occasionally look here. I like to help young people as long as they are anxious to learn how to solve, not just browse and look for ready solution of their problem. This is the case in this thread.
And I agree - if I can not verify/duplicate what some people calculated, I do not use their calculations.
This is a good thread, it demonstrates how are people able to help each other.
@Speedracerfast : You have two excellent sources for your dxf's; compare it and decide what to do next!

 

[Speedracerfast]

Wow thanks everyone for the help! Once again I appreciate the knowledge.

As for my last post, what I meant to say was "fully define" the spline the way I measured it described above, then use that model to measure other features that are spline specific. I know I need more info to put on the drawing, hence why I came here for help . Turns out it won't work well doing it this way anyways.

Now it's time to compile all these up, check calculations (as you all recommended). Because I'd like to know how to do this myself in the future; very useful skill to have.

If it doesn't break my NDA, I'll post some prototype 3D prints that come in soon. I also changed my bearings for the 100th time, and sourced a similar bearing (automotive specific.. same bearing used on many other cars today). Now I can copy pre-load specifications and have confidence for 70k-100k mile life.

Super close to done!

 

[spigor]

Learning the difference between involute spline and serration might be a good start.

 

[Speedracerfast]

Spigor,

When I pop in your dxf file into solidworks or eDrawings (to compare to mine), the dimensions are way off. I'm getting a diameter of around 24 inches. Am I missing something here?

 

[Speedracerfast]

Nevermind sorry. It was a solidworks problem I believe. I imported it via mm instead inches and it came back to scale. Matches well with mine too. Thanks lfw618 for that modeling tip and Spigor for dxf