Position sensor for detecting angular position

Claim 1

A crankshaft position sensor for measuring angular position of a crankshaft of a multi-cylindered internal combustion engine, comprising: (a) a magnetic tubular member comprised of a ferrite material having a center shaft fixed coaxially therewith, said tubular member being rotatable synchronously with the rotation of the engine crankshaft and having a plurality of magnetized zones arrayed along an axis of rotation formed on its peripheral surface, one of said magnetized zones having a pair of magnetic poles and the others having a plurality of pairs of magnetic poles not less than the number of cylinders of the engine, said magnetized zones each having a non-magnetized portion interposed between the magnetic pole pairs in the direction of rotation and sandwiching a non-magnetized zone along the axis of rotation, each said non-magnetized zone having a width along the axis of rotation not less than that of each of said magnetized zones; and (b) a plurality of magneto electric transducer means in a number of same as that of said magnetized zones arrayed along the axis of rotation and disposed on a stationary member independent of said rotating tubular member while facing said rotating tubular member at a predetermined distance, said magneto electric transducer means having a magneto-sensitive surface which is greater in width along the axis of rotation than each of said magnetized zone.