Title:
FREQUENCY DETERMINATION METHOD FOR CONSTANT VOLTAGE AC FED TO TORQUE SENSOR DETECTION COIL
Document Type and Number:
Japanese Patent JP3440664
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To lessen sensor characteristic dispersion without any change of sensitivity by determining the frequency of constant voltage alternating current fed to a detection coil, so as to minimize the fluctuation of the impedance change rate of the detection coil for an axial change in the relative position of upper and lower sensor ring teeth.
SOLUTION: An upper sensor ring 21 and a lower sensor ring 22 are coaxially arranged at the prescribed radial gap, so as to be faced to each other for maintaining the axial superposed length (overlapped length) of tooth parts 21a and 22a at the prescribed value. Also, the sensitivity of a detection coil 25 increases, according to a drop in the frequency of supplied constant voltage alternating current, and lowers, according to an increase in the frequency. In this case, therefore, the frequency of the constant voltage alternating current fed to the coil 25 from an oscillator is set at such a value as capable of minimizing the fluctuation of sensitivity for the change of the overlapped length of the tooth parts 21a and 22a, thereby reducing the dispersion of a sensor characteristic due to the axial irregularity of the relative position of the sensor rings 21 and 22 resulting from an assembly error or the like.
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Inventors:
Jun Onoda
Application Number:
JP32071695A
Publication Date:
August 25, 2003
Filing Date:
December 08, 1995
Export Citation:
Assignee:
Toyota Koki Co., Ltd.
International Classes:
G01L3/10; (IPC1-7): G01L3/10
Domestic Patent References:
| JP7294346A | ||||
| JP9105687A |