Patent ID: 9360494
Filing Date: 2016-06-07
CPC Classification: G01D,G01P

Claim Text:
1. A rotation detector including a rotor, a magnetic field generator fixed to face said rotor and generates a magnetic field, and a detector unit arranged between said rotor and said magnetic field generator to detect signals that vary responsive to changes in said magnetic field caused the rotation of said rotor; wherein said rotor includes a first cylindrical portion having one or a plurality of steps, and a second cylindrical portion having one or a plurality of steps and arranged concentrically with said first cylindrical portion and being deviated in the axial direction; and said second cylindrical portion includes a first partial circumferential surface having a width narrower than that of said first cylindrical portion in the circumferential direction, and a second partial circumferential surface having a radius smaller than a radius of said first partial circumferential surface; said rotor, further, including: a first to-be-detected portion having a plurality of teeth formed on each of the steps of said first cylindrical portion; and a second to-be-detected portion having at least one tooth in phase with, and in the same shape and size as, the tooth of said first to-be-detected portion, said at least one tooth being formed on said first partial circumferential surface of said second cylindrical portion; wherein said at least one tooth of said second cylindrical portion and a tooth of said first cylindrical portion corresponding to said at least one tooth are formed in one operation by machining; and wherein said second partial circumferential surface of said second cylindrical portion is positioned on the inside of the bottom of teeth of said first to-be-detected portion in the radial direction.