Abstract: A helical phaser bias spring including at least one linear region and an adjacent region having a radius of curvature less than that of the helix. A channel in the phaser receives the linear region of the spring and adjacent region to lock the spring to the phaser at either the rotor or the stator. Preferably, the spring includes two linear regions separated by a bend of about 90°. Additional linear regions are possible, separated by right and/or other angle bends. In a phaser rotor or stator, the geometric shape required to hold a spring end having a flat is easier to form with powdered metal tooling or diecasting than is a circular, radial, or axial shape for receiving a spring tang as in the prior art, the packaging volume required for the spring is smaller, and spring friction is lowered.

Abstract: A method for intentionally imbalancing one or more mass elements of a camshaft assembly to provide overall rotational balance to the assembly, also referred to herein as “zero balance”. Such intentional imbalance may be imparted to any element of a camshaft assembly. In a currently-preferred embodiment, one or more components of an improved camshaft phaser assembly are manufactured as rotationally unbalanced, either by intentionally forming an unbalanced component such as a sprocket wheel having added material or by removing non-functional material from an otherwise standard component. Because the camshaft phaser assembly has a unique and fixed angular relationship to the camshaft, zero balance can be readily and repeatedly achieved for all camshaft assemblies by correct manufacture of parts without requiring separate balancing for each individual camshaft assembly as manufactured.

Abstract: A helical phaser bias spring including at least one linear region and an adjacent region having a radius of curvature less than that of the helix. A channel in the phaser receives the linear region of the spring and adjacent region to lock the spring to the phaser at either the rotor or the stator. Preferably, the spring includes two linear regions separated by a bend of about 90°. Additional linear regions are possible, separated by right and/or other angle bends. In a phaser rotor or stator, the geometric shape required to hold a spring end having a flat is easier to form with powdered metal tooling or diecasting than is a circular, radial, or axial shape for receiving a spring tang as in the prior art, the packaging volume required for the spring is smaller, and spring friction is lowered.