Axially compact electrically driven camshaft phaser

摘要

A camshaft phaser (10) for controllably varying the phase relationship between a crankshaft and a camshaft (22) of an internal combustion engine (18) includes a housing (42) having a bore (46) with an open end (50) and extending along a longitudinal axis (48). The camshaft phaser (10) also includes a harmonic gear drive unit (12) having an outer first spline (26), an outer second spline (28) which is axially adjacent to the outer first spline (26) and disposed within the housing (42), a flexspline (30) disposed radially within the outer first spline (26) and the outer second spline (28), a wave generator (32) disposed radially within the flexspline (30), and a rotational actuator (14) connectable to the wave generator (32) such that rotation of the rotational actuator (14) causes relative rotation between the outer first spline (26) and the outer second spline (28). The outer first spline (26) is fixed to the housing (42) in order to prevent relative rotation therebetween and serves to close the open end (50) of the housing (42).