Patent ID: 8622037
Filing Date: 2014-01-07
Classification: F01L

Abstract:
1. 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 bore with a longitudinal axis and an array of internal splines formed within said bore; 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 disposed within said flexspline, and a rotational actuator connectable to said wave generator such that rotation of said wave generator causes relative rotation between said circular spline and said dynamic spline, wherein one of said circular spline and said dynamic spline is fixed to said housing in order to prevent relative rotation therebetween; an output 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; a back plate having an array of external splines engaged in a sliding fit with said array of internal splines for transmitting torque from said back plate to said housing, said external splines and said internal splines preventing binding between said output hub and said housing, said back plate also having an input sprocket for receiving rotational motion, in use, from said crankshaft.