Bearing sensor having magneto resistive elements

A bearing sensor comprising:

• a plane coil having two pairs of opposed conductor sides parallel to one another,
• the two pairs of the opposed conductor sides constituting at least partially four sides of a rectangle,
• the opposed conductor side pair composed of a first side and a second side,
• two magneto resistive element planes located at both sides of the plane coil and being parallel to and adjacent to the plane coil,
• each of the magneto resistive element planes having four magneto resistive thin plates having a longitudinal direction crossing only a single side of the opposed conductor side pair at an angle of more than 30 degrees and less than 90 degrees,
• wherein two magneto resistive thin plates of which the longitudinal directions cross a pair of the opposed conductor sides and are not parallel to one another constitute a magneto resistive element pair of the magneto resistive thin plates having a first magneto resistive thin plate and a second magneto resistive thin plate, the first and the second magneto resistive thin plates being applied opposite magnetic fields by a DC current flowing through the plane coil,
• each of the magneto resistive thin plates electrically connected at one terminal thereof to the other and a voltage for measuring bearings is applied between the other terminals so that a potential is taken out from the one terminal according to bearings.

A bearing sensor comprising:

• a magneto resistive element plane and
• two plane coils located on both sides of the magneto resistive element plane and being parallel to and adjacent to the magneto resistive element plane,
• each of the two plane coils having at least two pairs of opposed conductor sides, the two pairs of the opposed conductor sides constituting at least four sides of a rectangle, the opposed conductor side pair composed of a first side and a second side which are parallel to one another,
• the magneto resistive element plane having two magneto resistive thin plates per a side of the opposed conductor side pair of the plane coils, the two magneto resistive thin plates having longitudinal directions crossing only the side of the opposed conductor side pair at an angle of more than 30 degrees and less than 90 degrees and being not parallel to one another,
• wherein a magneto resistive element pair is composed of one of the magneto resistive thin plates crossing the first side of the opposed conductor side pair of the two plane coils and the magneto resistive thin plate crossing the second side of the opposed conductor side pair of the two plane coils and being not parallel to the longitudinal direction of the one of the magneto resistive thin plates, and each of the magneto resistive thin plates electrically connected at one terminal thereof to the other and a voltage for measuring bearings is applied between the other terminals so that an intermediate potential is taken out from the one terminal according to bearings.

A process for bearings, comprising the steps of providing a sensor comprising:

• a plane coil having two pairs of opposed conductor sides,
• the opposed conductor side pair composed of a first side and a second side which are parallel to one another, and
• at least one magneto resistive element pair of two magneto resistive thin plates located on a plane parallel to and adjacent to the plane coil,
• the magneto resistive element pair having a first magneto resistive thin plate and a second magneto resistive thin plate,
• the first magneto resistive thin plate of the magneto resistive element pair having a longitudinal direction crossing only the first side at an angle of more than 30 degrees and less than 90 degrees,
• the second magneto resistive thin plate of the magneto resistive element pair having a longitudinal direction crossing only the second side at an angle of more than 30 degrees and less than 90 degrees,
• the longitudinal direction of the first magneto resistive thin plate being not parallel to the longitudinal direction of the second magneto resistive thin plate,
• each of the magneto resistive thin plates electrically connected at one terminal thereof to the other,
• passing a first DC current through the plane coil to apply to the magneto resistive thin plates a DC magnetic field enough to saturate a magnetization of the magneto resistive thin plates in the longitudinal direction of each of the magneto resistive thin plates,
• passing a first biasing DC current opposite to the first DC current through the plane coil to apply a biasing DC magnetic field perpendicular to the longitudinal direction,
• applying a voltage for measuring bearings between the other terminals of the magneto resistive element pairs to take out a first intermediate potential from the connected terminals of the magneto resistive element pairs during the application of the biasing DC magnetic field,
• passing a second DC current opposite to the first DC current through the plane coil to apply to the magneto resistive thin plates a DC magnetic field enough to saturate a magnetization of the magneto resistive thin plates in the longitudinal direction of each of the magneto resistive thin plates,
• passing a second biasing DC current opposite to the second DC current through the plane coil to apply a biasing DC magnetic field perpendicular to the longitudinal direction,
• applying a voltage for measuring bearings between the other terminals of the magneto resistive element pairs to take out a second intermediate potential from the connected terminals of the magneto resistive element pairs during the application of the biasing DC magnetic field, and
• obtaining a difference between the first and the second intermediate potentials to measure bearings from the difference.