Abstract: A magnetostrictive torque sensor system stabilizes and detects steering torque applied to a steering shaft.

Abstract: A magnetostrictive torque sensor includes first and second magnetostrictive films which are provided at a shaft and have different magnetic anisotropies; a first measurement coil and a second measurement coil which face the first magnetostrictive film; and a third measurement coil and a fourth measurement coil which face the second magnetostrictive film. A torque applied to the shaft is measured based on a variation in magnetic characteristics of the first and the second magnetostrictive films; and a failure of the magnetostrictive torque sensor is detected based on a first difference between output values from the first and the second measurement coils and a second difference between output values from the third and the fourth measurement coils. An electric steering system includes the magnetostrictive torque sensor for measuring a steering torque of the system; and an electric motor driven based on the measured magnetostrictive torque for steering the vehicle.

Abstract: A magnetostriction-type torque sensor 20 includes a shaft 12b formed of a magnetic material and provided with at least magnetostrictive films 20b and 20c; exciting coils 20d? and 20e? for exciting the magnetostrictive films 20b and 20c provided on the shaft 12b; detection coils 20d and 20e for detecting a change in a magnetic field; and yoke portions 20f respectively provided around outer peripheries of the exciting coils 20d? and 20e? and the detection coils 20d and 20e, wherein a magnetic shield section 20a formed of a magnetic material is provided around the outer peripheries of the yoke portions 20f.

Abstract: A magnetostrictive torque sensor includes first and second magnetostrictive films which are provided at a shaft and have different magnetic anisotropies; a first measurement coil and a second measurement coil which face the first magnetostrictive film; and a third measurement coil and a fourth measurement coil which face the second magnetostrictive film. A torque applied to the shaft is measured based on a variation in magnetic characteristics of the first and the second magnetostrictive films; and a failure of the magnetostrictive torque sensor is detected based on a first difference between output values from the first and the second measurement coils and a second difference between output values from the third and the fourth measurement coils. An electric steering system includes the magnetostrictive torque sensor for measuring a steering torque of the system; and an electric motor driven based on the measured magnetostrictive torque for steering the vehicle.

Abstract: In a torque sensor having a magnetic metal film with magnetic anisotropy attached to a torque transmission shaft, and an exciting coil and a pair of detector coils each installed near the magnetic metal film, outputs of the detector coils and a reference signal are respectively added in waveform adders when the exciting coil is energized by an exciting power source. Then, the outputs of the adders and the reference signal are respectively compared in phase in phase comparators, and the outputs of the comparators are respectively converted in voltage values. A differential amplifier amplifies a difference between the voltage values, and a torque detector detects direction and magnitude of the torque applied to the torque transmission shaft from polarity and magnitude of the difference voltage value, thereby enabling to accurately detect applied torque even when installed near noise-producing electrical equipment such as an electric power steering system.

Abstract: In a torque sensor having a magnetic metal film with magnetic anisotropy attached to a torque transmission shaft and an exciting coil and a detector coil each installed near the magnetic metal film, there is provided a reference voltage generator that supplies an ac excitation signal whose reference voltage indicating a midpoint of the ac excitation signal is set to a voltage corresponding to a 50% duty ratio of the ac excitation signal, to the exciting coil, such that a torque applied to the torque transmission shaft is detected based on an output of the detector coil, thereby achieving improved torque detection accuracy by enabling generation of an excitation signal of large amplitude that is free of upper-lower imbalance relative to the reference voltage as the midpoint and accurate detection of the magnitude and accuracy of detection waveform amplitude.

Abstract: A rotational torque detection mechanism is provided, which includes a rotational shaft whose first end portion reaches outside the mechanism, a magnetostrictive membrane which is disposed on a surface of the rotational shaft and varies its magnetic permeability according to an amount and direction of rotational torque acting on the rotational shaft, an excitation circuit which is disposed to confront the rotational shaft so as to excite the magnetostrictive membrane and a detection circuit which is disposed to confront the rotational shaft so as to electrically detect a change of the magnetic permeability of the magnetostrictive membrane. In the rotational detection mechanism, the first end portion is adapted to be a free end and a second end portion of the rotational shaft is rotatably supported.

Abstract: For forming an annular magnetostrictive coat on an outer peripheral surface of a rotational shaft associated with a magnetostrictive torque sensor, a magnetostrictive-coat forming method comprises a step of fitting a cylindrical masking jig over the outer peripheral surface of the rotational shaft and securing the masking jig to the outer peripheral surface, a step of placing the rotational shaft in a plating tank to thereby form the magnetostrictive coat by plating on the outer peripheral surface, and a step of detaching the masking jig from the rotational shaft.

Abstract: A magnetostriction-type torque sensor 20 includes a shaft 12b formed of a magnetic material and provided with at least magnetostrictive films 20b and 20c; exciting coils 20d′ and 20e′ for exciting the magnetostrictive films 20b and 20c provided on the shaft 12b; detection coils 20d and 20e for detecting a change in a magnetic field; and yoke portions 20f respectively provided around outer peripheries of the exciting coils 20d′ and 20e′ and the detection coils 20d and 20e, wherein a magnetic shield section 20a formed of a magnetic material is provided around the outer peripheries of the yoke portions 20f.

Abstract: A rotational torque detection mechanism is provided, which includes a rotational shaft whose first end portion reaches outside the mechanism, a magnetostrictive membrane which is disposed on a surface of the rotational shaft and varies its magnetic permeability according to an amount and direction of rotational torque acting on the rotational shaft, an excitation circuit which is disposed to confront the rotational shaft so as to excite the magnetostrictive membrane and a detection circuit which is disposed to confront the rotational shaft so as to electrically detect a change of the magnetic permeability of the magnetostrictive membrane. In the rotational detection mechanism, the first end portion is adapted to be a free end and a second end portion of the rotational shaft is rotatably supported.

Abstract: In a torque sensor having a magnetic metal film with magnetic anisotropy attached to a torque transmission shaft and an exciting coil and a detector coil each installed near the magnetic metal film, there is provided a reference voltage generator that supplies an ac excitation signal whose reference voltage indicating a midpoint of the ac excitation signal is set to a voltage corresponding to a 50% duty ratio of the ac excitation signal, to the exciting coil, such that a torque applied to the torque transmission shaft is detected based on an output of the detector coil, thereby achieving improved torque detection accuracy by enabling generation of an excitation signal of large amplitude that is free of upper-lower imbalance relative to the reference voltage as the midpoint and accurate detection of the magnitude and accuracy of detection waveform amplitude.

Abstract: In a torque sensor having a magnetic metal film with magnetic anisotropy attached to a torque transmission shaft, and an exciting coil and a pair of detector coils each installed near the magnetic metal film, outputs of the detector coils and a reference signal are respectively added in waveform adders when the exciting coil is energized by an exciting power source. Then, the outputs of the adders and the reference signal are respectively compared in phase in phase comparators, and the outputs of the comparators are respectively converted in voltage values. A differential amplifier amplifies a difference between the voltage values, and a torque detector detects direction and magnitude of the torque applied to the torque transmission shaft from polarity and magnitude of the difference voltage value, thereby enabling to accurately detect applied torque even when installed near noise-producing electrical equipment such as an electric power steering system.

Abstract: A torque detecting device includes a pair of fixed portions are provided on a rotating shaft to have a predetermined distance in an axially longitudinal direction, a permanent strain portion which changes a magnetostrictive characteristic corresponding to an applied torque is provided between the fixed portions, and a multilayered solenoid winding coil for electrically detecting a magnetostrictive effect produced in the permanent strain portion is provided around the permanent strain portion. The permanent strain portion is a portion in the rotating shaft to which a permanent strain is applied by twisting the fixed portions.

Abstract: A torque detecting device has such a structure that a pair of fixed portions are provided on a rotating shaft to have a predetermined distance in an axially longitudinal direction, a permanent strain portion which changes a magnetostrictive characteristic corresponding to an applied torque is provided between the fixed portions, and a multilayered solenoid winding coil for electrically detecting a magnetostrictive effect produced in the permanent strain portion is provided around the permanent strain portion. The permanent strain portion is a portion in the rotating shaft to which a permanent strain is applied by twisting the fixed portions.