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RFACATguy (Mechanical) (OP)
21 Apr 09 13:33
i don't have much experience with splines so i was wondering if anyone can help me with understanding the formulas for calculating the dimension between pins for a 30 degree flat root side fit 14 tooth 12/24 internal spline.  i'm not sure how to calculate the pressure angle at pin center mostly.  thanks in advance

fyi, i do have ANSI B92.1 in front of me on page 96
gearguru (Automotive)
21 Apr 09 21:42
What is the problem?
I do not have that standard on hand, but as far as I know, you should be able to calculate the
 
inv(of the pressure angle at the pin center)
 
From it the pressure angle can be calculated.
  
dinjin (Mechanical)
22 Apr 09 1:27
The method for internal gears or internal splines are the same so if you have a handbook for internal gears, the method will be defined there.  You have to use a pin size that does not bottom out in the root.
gearguru (Automotive)
22 Apr 09 9:28
The method is the same, the math/formulas behind it is for certain parts of calculation different. The calculation of the involute of the pressure angle to the center of the pin is one of them.
mfgenggear (Aerospace)
23 Apr 09 11:26
Gearguru
 the calcs are the same I use the same program I wrote to verify splines or gears.

Rfacatguy

If this is a one time issue it's easier just to use software all ready written.

if you still need more info

This is a good book to start with Spur & Helical gear problems. Invo spline Company.if you can find it ?


  
gearguru (Automotive)
23 Apr 09 15:31
I do not want to go into details here. The calculation/formulas can be the same, but only if you (or your program) is using the DIN method of entering the number of teeth for internal gears/splines as a negative number.
I also have couple of my calculations for the over/between pins/balls and . In VB, as a spreadsheet, as a htm file (javascript).
I agree that using a ready made calculation is OK, but I also believe that to understand how the formulas work and what they geomtrically mean is very important.
RFACATguy can learn a lot doing his own calculation "from scratch".   
tbuelna (Aerospace)
24 Apr 09 20:36
RFACATguy,

From ANSI B92.1-1996, page 104:

measurement between 0.1440 dia pins for max actual space width on a class 5, 14 tooth, 12/24 pitch, internal involute spline: 0.9609 inch.

A few years ago, a company called Van Keuren that makes gauge wires published a very nice reference book that gave you hundreds of tables for over/between pin dimensions of splines and gears.  Don't know if the book is still available though.  Try contacting them or looking on ebay.

http://www.vankeuren.com/tmw.aspx

Regards,
Terry

 

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