Position detection apparatus and manufacturing method of the same

摘要

A position detection apparatus includes a magnetic generator, a magnetic detector, a storage, and a rotation angle calculator. The rotation angle calculator calculates a relative rotation angle of the magnetic generator with respect to the magnetic detector based on a voltage output from the magnetic detector and a relational expression of θ=sin−1((VH−c)/V0)−b. In the relational expression, the relative rotation angle is defined as θ, the voltage output from the magnetic detector is defined as VH, a true maximum value of the voltage output from the magnetic detector is defined as V0, a first true correction value is defined as b, and a second true correction value is defined as c.

主权项

1. A position detection apparatus comprising:
a magnetic generator; a magnetic detector that outputs a voltage corresponding to a change of a magnetic flux density generated by a relative rotational movement between the magnetic detector and the magnetic generator; a storage that stores a relational expression indicating a relationship between a relative rotation angle of the magnetic generator with respect to the magnetic detector and the voltage output from the magnetic detector; and a rotation angle calculator electrically coupled to the magnetic detector and the storage, the rotation angle calculator calculating the relative rotation angle of the magnetic generator with respect to the magnetic detector based on the voltage output from the magnetic detector and the relational expression stored in the storage, wherein, when the relative rotation angle of the magnetic generator with respect to the magnetic detector is defined as θ, the voltage output from the magnetic detector corresponding to the rotation angle θ is defined as VH, a true maximum value of the voltage output from the magnetic detector is defined as V0, a first true correction value that corrects a position shift of the magnetic generator with respect to the magnetic detector in a rotational direction of the relative rotational movement is defined as b, and a second true correction value that corrects a position shift of the magnetic generator with respect to the magnetic detector in a direction perpendicular to the rotational direction is defined as c, the relative rotation angle is calculated by the relational expression of: θ=sin−1((VH−c)/V0)−b, wherein, the true maximum value, the first true correction value, and the second true correction value are calculated by the rotation angle calculator based on a first relative rotation angle, a first voltage, a second relative rotation angle, a second voltage, and a third relative rotation angle, wherein the magnetic detector outputs the first voltage when the relative rotation angle of the magnetic generator with respect to the magnetic detector is equal to the first relative rotation angle, wherein the magnetic detector outputs the second voltage when the relative rotation angle of the magnetic generator with respect to the magnetic detector is equal to the second relative rotation angle, and wherein the magnetic detector outputs the voltage having a value of zero when the relative rotation angle of the magnetic generator with respect to the magnetic detector is equal to the third relative rotation angle.