Quote:
Originally Posted by squirrel
I was pondering making the shaft to plate joint a press fit. I think it would be relatively easy to get the size for round part of the hole figured out, but I wonder what the tolerance is on the flats on the shaft. If they vary by more than a thousandth of an inch, it would be challenging to get a reliable fit.
It would be really nice from the viewpoint of the wear we are seeing....I know in automotive transmissions, once splines start to get loose, they wear out quickly.
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I think that we have pretty much put to bed the idea that the carriers can be easily hardened (by teams or even by a "swap service" of some kind).
I think the urgency of getting the mat'l analysis is lessened.
As to the tight fit, this is going to help some but my theoretical analysis/calculations do not show a significant improvent in this case (nothing like what I expect we need).
Here is my current thinking of most likely patches:
#1 harder carriers (= to the shaft hardness) address all the 1-CIM cases (16:1 & 12:1)
#2 harder (perhaps RC 40-45) carriers plus redesigned joint (e.g. square hole) plus harder (again perhaps RC 40-45) shafts (with mating joint) address all the 2-CIM cases (IF, and this is a big IF, tests show 2-CIMs stress the joint beyond what is done in #1 -- note that motor torque is not the only thing that determines the torque this joint sees, friction is another and it may limit the torque that the joint sees to something close to the 1-CIM number)
Stay tuned.
Joe J.