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

 

[mfgenggear]

Verifying with the mow instead of gages pinches the tolerance. With gages the max mow becomes a ref .

 

[mfgenggear]

@speedracerfast
A small # of parts it more reasonable to edm or shape
A broach has a long lead time, and can be very expensive.
But with a large number of parts it can be
Amortized into the cost.

Contact Forest City gear in Illinois.
Or broach Masters Inc in ca.
Or look for gear shops that advertise
Reverse engineering there are a few.
But my mind is blank do to a darn headache

 

[spigor]

I know a good shop that could handle this in Europe, in the US I'd recommend this:

https://www.geartechnology.com/dir/

https://gearsolutions.com/community/

Also downloading the latest issues of these magazines in pdf free of charge and there are tons of ads inside.

 

[spigor]

The reason I have written "fillet root" in the specs is because there appears to be no flat root version for that 45° spline in the ANSI B92.1-1996. Long story short- on an internal spline that "fillet root" has more to do with the major dia. than with the real shape of the root itself. The shape depends more on the technology it has been made with. A broach will in most cases make almost no rounding. A standard shaper cutter will make a small trochoid shaped rounding, when a bigger fillet is needed it must be calculated and modified (which by the way is not an easy task and I'm very proud of being able to control the fillet or chamfer making in gear and spline shaping). WEDM will inevitably make a rounding.
A flat root spline would also work with your mating part, which has been proven because the green plot from me fits.
If you want you can leave the "fillet root" out of the description, since no other 45° version seems to exist in the standard.

If that's good you have got everything ready and proven with numerous measurements and checking with the mating part made to the green plot, except for the class (assuming it is ANSI B92.1, but that looks like a pretty safe assumption to me). Maybe you could put both mating parts together, place a dial indicator tangentially on a given radius and check how much rotational backlash you have on that radius? Not going into too much detail with the effective and actual dimensions, you could see how much space width difference there is between Class 5, 6 and 7 on the pitch diameter of 1", scale your measuring diameter to 1" and see how many .001s would you like to take away, hence finding out what class do you need.

@mfgenggear: a headache again?

 

[mfgenggear]

@mfgenggear makes sense but I need to sleep on that info. I'm just confused on your last two sentences there:

"But with out gages there is an over tighten of tooth thickness size.
A gage gives more tolerances."

@speedracerfast

all the above are in the ANSI B92.1 obtain a copy and under stand it completely.
study the sections on spline gage design.
I have been designing spline gages for many years I had to under stand it very well.

@spigor
@mfgenggear: a headache again?

yes my eyes are getting tired, to much starring the computer LCD screens
even thou I have eye glasses, I have a problem with glare, always have for years.

 

[mfgenggear]

"If that's good you have got everything ready and proven with numerous measurements and checking with the mating part made to the green plot, except for the class (assuming it is ANSI B92.1, but that looks like a pretty safe assumption to me). Maybe you could put both mating parts together, place a dial indicator tangentially on a given radius and check how much rotational backlash you have on that radius? Not going into too much detail with the effective and actual dimensions, you could see how much space width difference there is between Class 5, 6 and 7 on the pitch diameter of 1", scale your measuring diameter to 1" and see how many .001s would you like to take away, hence finding out what class do you need."

actually that is a good plan, to make sure parts assemble use the existing parts to verify no interference when assembled.
and make sure they fit. measure twice cut once.
Just remember a class 5 spline can be cut to look like a class 4 or 7, because the max effective size on an external spline will accept the go gage.
I would say a class 5 spline would be safe. tighter class would be to give better back lash control.
but causes issues during heat treat, do to distortion.

 

[Speedracerfast]

"but causes issues during heat treat, do to distortion."

With that said, does anyone how what affects EDM will have on spline strength or distortion with 4340 alloy? I can't find concrete essays about the localized effects from cutting with this method. I am doing no post processing. This their general material page for 4340:

https://www.3dhubs.com/cnc-machining/metal/alloy-steel/alloy-steel-4340/

I misspoke earlier, 3-D hubs rep was persistent on power skiving to cut this spline. I told him that's not possible on an internal this small, that's when he back tracked to EDM. I understand broaching is for mass production, but I was thinking you can rent the tool if it's a standard spline or something. Not sure!

 

[Speedracerfast]

@mfgenggear for your headaches, maybe wearing Blue-Light-Filtering Lenses would help you out? I personally run blue light filter (close to max dim) 24/7 on all my computers. On windows it is located on the bottom right windows center... right click to alter how much it dims. College killed my eyes since everything I did mostly was through computer screen.

 

[mfgenggear]

17 Jun 20 20:22
"but causes issues during heat treat, do to distortion."

With that said, does anyone how what affects EDM will have on spline strength or distortion with 4340 alloy? I can't find concrete essays about the localized effects from cutting with this method. I am doing no post processing. This their general material page for 4340:

https://www.3dhubs.com/cnc-machining/metal/alloy-s...

I misspoke earlier, 3-D hubs rep was persistent on power skiving to cut this spline. I told him that's not possible on an internal this small, that's when he back tracked to EDM. I understand broaching is for mass production, but I was thinking you can rent the tool if it's a standard spline or something. Not sure!

The company's to verify with if they have a broach in stock would be ASH gear rent or buy and (Broach Masters Inc.)BMI rent but the would have to do the broaching.
send them a copy of the sketch.

3dhubs has no gear inspection equipment, I would not recommend them for that reason, they are not a gear shop.

If the parts are broached it would have to have a interim heat treat Normalize, Harden and temper to 30-36 HRc, then final heat treat after broach , unless a company has hard broaching capability.
same for shaping with a small shank type shaper cutter. again check with ash gear , google them.
with wire cut ask for .0005 max recast layer, on heat treated parts .001 max decarb is normally permitted, hydrogen embrittlement relief after wire cut.
if fully heat treated with a hole to pass the wire thru, It would have to be wire cut with .006 wire to produce .010 max fillet root, and it's very slow going also expensive.

 

[mfgenggear]

@mfgenggear for your headaches, maybe wearing Blue-Light-Filtering Lenses would help you out? I personally run blue light filter (close to max dim) 24/7 on all my computers. On windows it is located on the bottom right windows center... right click to alter how much it dims. College killed my eyes since everything I did mostly was through computer screen.

@speedracerfast
I changed the PDF & Excel sheets to a light blue screen
see if that helps

 

[Speedracerfast]

@mfgenggear nice that should help. Also sitting in a dark room looking at a screen doesn't help too haha.

Overall update is my BD partner wants to proceed with 3D Hubs despite my warnings about the spline cut. I'm waiting on responses from ASH and Broach Masters. Waiting to hear back. 3D Hubs reviewing my finalized drawings, so if quote goes up I'll be looking somewhere else.

Furthermore, when my BD partner and I were talking, he reminded me of the aftermarket cv shafts that people run. They're really sloppy and have tons of backlash. He told me about half the cars left are using these CV shafts with no issues. This car probably makes no more than 250 wheel torque, plus remember the fact these are the rear hub/spindle assemblies with a electromagnetic clutch sending power to back;' it's not seeing feeling much torque.

I guess I've done my job *shrug* and given the warnings. I'll continue to work on other options though in case stuff goes wrong. Thank you all for the help and advice. I've learned and ton and keep learning. I'll post up about the gear soon.

 

[mfgenggear]

@speedracerfast
Thank you from all of us
For the kind words and the update.
Best
Lee