Patent ID: 7008191

Claim:
A compressor wheel assembly comprising: a compressor wheel mounted to a rotating shaft, said shaft extends through a bore provided along the rotational axis of the wheel, said shaft and wheel including keying formations; a nut which threads on one end of the shaft and bears directly or indirectly against a nose portion of the wheel to clamp the wheel against an abutment and prevent axial movement of the wheel alone the shaft; a drive washer having an inner aperture to receive said shaft and which is disposed around said shaft between the nut and the wheel, the drive washer having inner and outer keying formations which engage the shaft and wheel keying formations respectively; and wherein the wheel keying formations comprise recesses extending radially into the wheel and the outer keying formations of the drive washer comprise radial projections which engage in said recesses, and said wheel is keyed to the shaft such that the rotation of the shaft drives rotation of the wheel through the keying engagement.