Involute Spline Reverse Engineering 2

[GrandMax]

First post.

I just did a reverse engineering of a splined hub I need to replicate (different driveline).

Certainly metric, I deduced that the spline were 30 degrees, with a module of 1mm and 12 teeth. I measured the shaft and hub diameters over pins according to DIN5480 (2.5mm for the shaft, 1.75mm for the hub) to be as follow:

17.23mm@2.5mm
10.56mm@1.76mm

Using Kisssoft and DIN5480, I found out it was not actually the default profile shift 0.45mm. Therefore, I used the above measurement to compute a new profile shift coef. of .555mm. Measurement over pins now checks out.

However, the tip and root diameter are way off for both the shaft and hub.
Shaft root is measured at 11.20mm instead of designed 12.01mm.
Shaft tip is measured at 13.75 instead of 14.01mm.
Hub tip is measured at 13.96mm instead of designed 14.22mm.
Hub root is measured at 12.08mm instead of designed 12.21mm.

The splines may be JIS. 1. Could this explain the difference? Kisssoft does not have the JIS standard integrated.
2. Does it matter? My understanding is that they will fit properly if the diameter over pin is right. 3. Should I change my hub diameters or let them as designed?

Thank you for your help?

 

[gearcutter]

First download this to help you confirm the pitch and pressure angle.

http://www.artec-machine.com/_images/documents/Base_Pitch_Tables.pdf

Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[GrandMax]

Thanks a lot.

I double-checked the base pitch. If my assumptions were right; it should be 2.72mm.

I measured, using the method you recommend, 2.68mm, a result that seems reasonably closed, considering the relative size of the shaft.

So the variation is diameter over pins would be related to a profile shift different then the default 0.45mm, right?

I am looking forward to hearing what you think.

Cheers,

Max

 

[gearcutter]

Looks like it's as per DIN 5480-2006 14x1x30x12x9H 8f, side fit.

Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[GrandMax]

Thank you.

It indeed looks like that. However the diameter over pins are different.

I measured the shaft and hub diameters over pins to be as follow:

17.23mm@2.5mm
10.56mm@1.76mm

I thought the error was too large, hence the attempt to change the profile shift (Kisssoft matches it automatically with the measured value). With 0.555, I had a perfect match but the tip/root diameter are not good anymore.

Here is the hub spline table with the modified profile.

Spline data, Hub
DIN5480 14.21x1.00x30x12x7H
Nominal diameter 14.21
Modulus 1.00
Pressure angle 30
Number of teeth 12
Face Width 31
Reference diameter 12
Basic diameter 10.392
Profile correction (x*m) 0.555
Dimension over 2 needles 10.585/10.614
Needle diameter mm 1.75
Tooth root diameter 14.21
Tooth tip diameter 12.21

Hence the following question:
1. Is this new hub going to fit on the older shaft?
2. Should I shift the profile like that? Or keep it as you shown?
3. 14.2mm or 14mm?

Thanks a lot for your help. It is really appreciated.

 

[GrandMax]

Edit: I'll go to 9H. 7H is unnecessarily tight for the application.

 

[GrandMax]

Just realized the internal spline over measurement was wrong. The pin is too small to make contact with both flanks. It touches the root diameter. Hence a small error.

The pin I used is 1.75mm.

Why is that? Shouldn't be like that?

 

[GrandMax]

The root diameter is actually smaller than what it should be.

Remeasured several times at 13.80mm (only have a caliper). That could explain why the pins does not go in deep enough.

I still don't know how to reproduce those splines? Please help.

 

[gearcutter]

To provide clearance between pins and minor diameters; it is not uncommon to a grind a flat on to each pin.
Vernier callipers aren't the best thing to use when measuring small diameters as the contact points will be the edges of the jaw's flats.
The best thing to do in this case is to take a measurement between a pair of equally sized pins, that are small enough to only make contact with the internal major diameter, then just add the diameters of the two pins to the measurement you take to get your major diameter.
If you find that the internal major diameter is very close to the external major diameter then it is possible that you have a 'major diameter fit' spline.
Having said that however; to keep within the DIN5480 standard, the diameters for your spline (if it's a major diameter fit) should be around 14mm.

Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181