Patent ID: 6630821
Filing Date: 2003-10-07
Classification: G01D

Abstract:
A magnetic detection device comprising:a magnet for generating a bias magnetic field; first and second magneto-resistance effect element units facing to a toothed magnetic movable body to be detected and located in moving direction thereof within the bias magnetic field of said magnet, and of which resistance changes according to change in condition of the bias magnetic field corresponding to movement of said object to be detected; a first resistance change output circuit for outputting change in resistance of said first magneto-resistance effect element units; a second resistance change output circuit for outputting change in resistance of said second magneto-resistance effect element units; and an output signal processing circuit for outputting a first signal according to phase difference between an output of said first resistance change output circuit and an output of said second resistance change output circuit based on the movement of said object to be detected in forward direction, and for outputting a second signal according to phase difference between outputs of said first and second resistance change output circuits based on the movement of said object to be detected in reverse direction; wherein the first magneto-resistance effect element unit is a serially connected unit composed of two magneto-resistance effect elements connected in series, and the second magneto-resistance effect element unit is a serially connected unit composed of two magneto-resistance effect elements connected in series; and wherein one magneto-resistance effect element of the first magneto-resistance effect element unit and one magneto-resistance effect element of the second magneto-resistance effect element unit are located in the center, and the other magneto-resistance effect element of the first magneto-resistance effect element unit and the other magneto-resistance effect element of the second magneto-resistance effect element unit are located on two sides sandwiching said magneto-resistance effect elements therebetween, in moving direction of the toothed magnetic movable body.