Patent ID: 7280937
Filing Date: 2007-10-09
Classification: C23C,F15B,G01D

Abstract:
1. A method for detecting a position of a shaft, the method comprising: providing a shaft comprising a hardened outer metallic layer having a first hardness level with a generally uniform radial depth; forming a first strip extending in a generally longitudinal direction in the hardened outer metallic layer, the first strip having a second hardness level different from the first hardness level; forming a second strip in the hardened outer metallic layer having the second hardness level, the first strip and the second strip spaced apart from each other over a longitudinal region; sensing an angular difference between a first magnetic field associated with the first strip and a second magnetic field associated with the second strip; and referencing an established relationship between a position of the shaft and the angular difference between the magnetic fields associated with the first strip and the second strip to detect a position of the shaft with respect to a reference point.