Patent ID: 8545125

Claim:
A connection between a shaft and a coupling, comprising: a shaft having a first end and a second end opposite said first end, wherein shaft splines are formed around an outer periphery of said shaft, said shaft splines being formed between longitudinally extending shaft grooves cut into an outer surface of said shaft; a coupling comprising an opening adapted to receive said shaft, said opening extending from a first end formed within said coupling to a second end formed at an outer surface of said coupling, wherein coupling splines are formed around an inner periphery of said opening, said coupling splines being formed between longitudinally extending coupling grooves cut into an inner surface of said opening, and wherein said shaft is inserted into said opening such that said first end of said shaft is located adjacent said first end of said opening, and said shaft splines are engaged with said coupling splines; wherein said coupling and said shaft are rotatable about a common central axis for torque transmission therebetween through said respective engaged splines and where one of said shaft grooves and said coupling grooves are cut in a manner that the width of each groove and the depth of cut of each groove with respect to said common central axis changes between the respective first and second ends thereof, while a major diameter of said splines formed between said one of said shaft grooves and said coupling grooves is substantially constant such that: when no rotational load is applied to the shaft, the shaft splines and coupling splines contact only at the respective first ends thereof, while when a rotational load is applied to the shaft spline contact area between said shaft splines and said coupling splines increases toward said second end of the coupling as said shaft deflects under loading.