Rotation angle detecting device for e.g. engine air intake control apparatus has magnetic resistor which detects rotation angle of rotator by detecting change in orientation of magnetic flux arising in permanent magnets in air gap

摘要

A magnetic resistor (12a,12b) is disposed in an air gap formed between magnetic members (11a,11b) to axially align with a rotator and fixed to a non-rotator. Each of the magnetic members has a projecting portion (11a1,11b1) pointed at the magnetic resistor and a wall portion (11a2,11b2) surrounding the magnetic resistor to prevent influence from external magnetic fields. Magnetic resistor detects the rotation angle of rotator by detecting the change in orientation of magnetic flux arising in permanent magnets in the air gap.