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Is there is a proper standard for designing choosing and straight coupling splines?

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St0RM33

Automotive
Dec 14, 2015
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Commonly used in vehicle transmission input shaft and axle shafts for example.

Shown below both internal and external types.

MN107628-mitsubishi-manual-transmission-input-shaft-evo-7-8-3_dpsxtv.jpg


381106-S-1620-competition-clutch-evo-sprung-disc-3_61925dee-e5b8-4290-8544-4dbc6f38761b_mdntw9.jpg
 
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SAE, ISO, and DIN all have standardized spline forms with supporting application notes. Poor lubrication conditions will add application specific challenges.
 
Sorry but both of those are not this type.
J499 is parallel sides and 510206 involute splines.

The ones i am talking about are serrated splines cut with a standard lathe cutting tool (usually 90 degrees but could be any angle you want technically if you match the coupling)

See the difference here (edit, not very clear between involute and serrated, serrated can still have less teeth so there is no need for each tooth to follow the immediate one after, involute is defined by the involute tooth profile that cannot be observed by the photo):

safasfasafasf_eefdo3.jpg


Here's a better section but still not 100% accurate:

wnxk_3e_kscj4f.gif



Also here are some videos showing how they are cut:





This type is the most commonly used spline because it's cheap and easy to make. Also it's probably better than the straight/parallel-sides spline because of less stress concentration and higher torque capacity, however this type is generally found in most agriculture PTO equipment still (probably due to legacy compatibility with older attachments)
 
I work with aircraft applications, but all three type of splines are used. how ever 45 deg, splines are a pita. I prefer involute splines.
45 deg splines change on size with any post operations.
 
Yes involute is the ideal spline form but requires special tooling to cut, that's why it's not as common especially for coupling splines. However it's very common in gear teeth.
 
Not strictly true. A rack with the correct straight flanked teeth will cut an involute into a shaft if it is progressively fed across as the shaft is rotated. You wouldn't do it that way by choice, but that's how it would have been done once upon a time


Thinking about oit an easier way would be to use a cutter with straight flanks, and put the shaft on the bed of the milling machine. I think that's how i did it at college

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376
 
Storm33

30 degree spline are very common.
for high volume spline rolling, for moderate production spline hobbing and shaping , low to high volume spline grinding. I mostly work with mostly ANSI B92.i, again aircraft applications.
if the parts are high volume the tooling is relative inexpensive because the tooling is amortized by quantity of parts. the required quality and runout required will dictate the machining method.
 
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