Patent ID: 8516983

Claim:
A camshaft phaser for controllably varying the phase relationship between a crankshaft and a camshaft in an internal combustion engine, said camshaft phaser comprising: a housing having a longitudinal axis; a harmonic gear drive unit disposed within said housing, said harmonic gear drive unit comprising a circular spline and an axially adjacent dynamic spline, a flexspline disposed within said circular spline and said dynamic spline, a wave generator assembly disposed within said flexspline, and a rotational actuator connectable to said wave generator assembly such that rotation of said wave generator assembly causes relative rotation between said circular spline and said dynamic spline, wherein said wave generator assembly includes an elliptical wave generator surrounded tightly with an inner race having an inner race axial end, an outer race surrounded tightly with said flexspline, a plurality of balls disposed between said inner race and said outer race, and a ball cage having an annular section disposed axial from said balls proximal to said inner race axial end and a plurality of ball separators extending axially from said annular section such that consecutive balls are separated by one of said ball separators, wherein one of said circular spline and said dynamic spline is fixed to said housing in order to prevent relative rotation therebetween; a hub rotatably disposed within said housing axially adjacent to said harmonic gear drive unit and attachable to said camshaft and fixed to the other of said circular spline and said dynamic spline in order to prevent relative rotation therebetween; and a rigid support ring fixed axially and extending axially beyond said inner race axial end toward said annular section to limit axial deflection of said annular section.