Rotational sensor with robust axial alignment tolerance

摘要

A rotation sensor for high accuracy angle applications such as internal combustion engine crankshaft position sensing includes a pair of complementary target wheels (25A,25B) and a dual-element magnetoresistive sensor (11). The target wheels (25A,25B) are paced from one another along the rotational axis (Ar) by a predetermined distance (L). The individual magnetoresistive elements (MR1,MR2) are similarly spaced one from the other (2d) and are influenced by the ferrite effects of the target wheels. The spacing of the target wheels and magnetoresistive elements are selected in relation to one another and in relation to the amount of axial play in the crankshaft such that changes in ferrite effects of the target wheels upon the elements due to axial displacement ( DELTA ) of the crankshaft have minimal effect on the accuracy of the sensing apparatus. <IMAGE>