Abstract:
A camshaft phaser for controllably varying the phase relationship between a crankshaft and a camshaft of an internal combustion engine includes a housing having a bore with an open and extending along a longitudinal axis. The camshaft phaser also includes a harmonic gear drive unit having an outer first spline, an outer second spline which is axially adjacent to the outer first spline and disposed within the housing, a flexspline disposed radially within the outer first spline and the outer second spline, a wave generator disposed radially within the flexspline, and a rotational actuator connectable to the wave generator such that rotation of the rotational actuator causes relative rotation between the outer first spline and the outer second spline. The outer first spline is fixed to the housing in order to prevent relative rotation therebetween and serves to close the open end of the housing.