Torque sensor

Abstract

A torque sensor which does not require complicated neutral adjustment using a position adjustment mechanism or the like, which is capable of reducing cost and heat generation, improving reliability and realizing a one-system detection circuit. A torque sensor has a control calculating portion for varying operation timing of a coil for detecting torque and sample holding timing and a storage portion for storing an initial value of each element of the torque sensor. The torque is detected on the basis of sampling of transition voltage of the coil and a comparison with the initial value in the storage portion is made during detection of the torque is not being performed so that a failure of each element of the torque sensor is detected. Another torque sensor structured to detect torque in accordance with transient voltages which are generated in the portion in which coils and electric resistors are connected to each other is enabled to detect an abnormality of short circuit between a pair of the coils. At timing at which the torque is not detected, only either of rectangular-wave control voltages is applied to a transistor. At timing synchronized with falling of the control voltage, output voltage is A/D-converted and read. In accordance with whether or not output voltage is the same as power supply voltage, short circuit between the coils is detected.