US Patent 7866293 Concentric camshaft with improved torque resistance

An engine assembly may include an engine structure and a camshaft supported on the engine structure. The camshaft may include a first shaft, a first lobe member fixed to the first shaft and including a bore and first and second lobe portions that are axially spaced from one another and fixed to one another. The bore may include a first radial inner surface at the first lobe portion and a second radial inner surface at the second lobe portion.