Impeller and shaft assembly for high speed gas compressor

Claim 1

A rotatable gas compressor impeller and shaft assembly comprising: a rotatable shaft having a threaded axial bore in its driving end; an impeller having an axial bore therethrough and adapted to be assembled to the driving end portion of said shaft with a fastener haing a threaded shaft passing through the impeller axial bore and threaded into said shaft bore; the rear face of said impeller having a socket surrounding the rear end of said axial bore in the impeller, the circumferential walls of said socket tapering slightly outwardly; said driving end portion of said shaft having a basically frusto-conical shaped extremity received in wedging relation in said socket, the circumferential wall of said extremity including a plurality of forwardly-open, axially-extending grooves circumferentially spaced therearound and alternating with intervening lands; said impeller socket being comprised of a material of lower compressive yield strength than the material forming the surface of said shaft extremity, and the circumferential dimension of said shaft extremity as defined by said lands being slightly larger than the facing circumferential dimension of the wall of said socket in the finally seated relation of said shaft extremity in the socket so that with said shaft extremity being wedged into place by said fastener the lands plastically deform the material of said impeller socket in an outward direction.