Patent ID: 8593137
Filing Date: 2013-11-26
Classification: G01N

Abstract:
1. An eddy current sensor comprising: a probe that has an exciting portion configured to apply a predetermined alternating-current excitation signal to a measurement object component, the exciting portion including a first excitation coil that is arranged so that a center axis direction of the first excitation coil is oriented in a first axis direction and a second excitation coil that is arranged to intersect with the first excitation coil so that a center axis direction of the second excitation coil is oriented in a second axis direction perpendicular to the first axis direction, and a detecting portion configured to detect a detection signal generated in the measurement object component owing to the applied alternating-current excitation signal, the detecting portion including a detection coil that is arranged at one of two intersecting portions of the first excitation coil and the second excitation coil; a computing unit configured to calculate the detection signal as a measured eddy current value, and a controller configured to apply an alternating-current voltage to each of the first excitation coil and the second excitation coil as the alternating-current excitation signal in a state where the probe is arranged in proximity to the measurement object component in position such that the detection coil faces a measured portion of the measurement object component, to generate a first magnetic field in the first axis direction and a second magnetic field in the second axis direction at a portion of the measurement object component, facing the detection coil, to generate eddy currents by the first and second magnetic fields, to obtain induced voltages generated by the eddy currents as the detection signal, the induced voltages being detected by the detection coil of the detecting portion, and to measure a hardness penetration of the portion of the measurement object component, facing the detection coil, on the basis of the measured eddy current value calculated by the computing unit from the detection signal, wherein the detecting portion includes one or two quenching determination coils that are arranged adjacent to the detection coil on one side or both sides in the first axis direction, and wherein the controller applies the alternating-current voltage to each of the first excitation coil and the second excitation coil as the alternating-current excitation signal in a state where the probe is arranged in proximity to the measurement object component in position such that the detection coil and each quenching determination coil face the measured portion of the measurement object component, generates a magnetic field in a direction perpendicular to the first axis direction and the second axis direction at a portion of the measurement object component, facing each quenching determination coil, generates eddy current by the magnetic field, obtains induced voltage generated by the eddy current as a detection signal, the induced voltage being detected by each quenching determination coil of the detecting portion, and to determine whether the portion of the measurement object component, facing each quenching determination coil, is quenched or not quenched on the basis of the measured eddy current value calculated by the computing unit from the detection signal of each quenching determination coil of the detecting portion.