PURPOSE: To make temp. compensation easy and high temp. operation possible by using ferromagnetic material reluctance effect elements for reluctance effect elements, and making the direction of the magnetic poles of the magnet that applies magnetic bias coincident with the tangential direction of a gear.
CONSTITUTION: A recess 4a is provided on the side of a permanent magnet 4 facing each tooth 2a, and a non-magnetic material substrate 6 deposited and formed with ferromagnetic material reluctance effect elements 7 on the side facing said teeth is fitted and disposed in said recess 4a. Since the tangential direction A of the gear 2 and the direction B of the magnetic bias by the magnet 4 are made roughly coincident, the bias magnetic field is applied roughly in the same direction as the tangential direction of the gear 2, and since the directions of the electric currents flowing to the elements 7 are in the intersecting directions, the change in the magnetic fields between the respective teeth 2a is largely sensed by the elements 7 in accordance with the presence or absence of the teeth 2a.
KANAI HIROMI
ODAWARA KOUZOU
