Non-contact power feeding device used in torque sensor having a coil enclosed in peripheral side of a resonance coil and is magnetically coupled with the resonance coil

A non-contact power-feeding device, comprising:

• a power transmitting unit that includes a first antenna coil, an oscillator and a driver that enables generation of an AC magnetic field via the first antenna coil based upon a signal provided by the oscillator;
• a power receiving unit that includes a second antenna coil that is magnetically coupled with the first antenna coil;
• and
• a torque measuring strain gauge engaged in operation on power provided by the power circuit, wherein:
• the first antenna coil comprises:
• a flat-plane spiral resonance coil wound with a plurality of turns;
• and
• a flat-plane spiral power-feeding coil that is wound with a plurality of turns outward relative to the resonance coil so as to surround the resonance coil, and is magnetically coupled with the resonance coil, wherein
• the power receiving unit further includes:
• a rectifier circuit that rectifies an AC signal induced at the second antenna coil;
• a power circuit, with an output of the rectifier circuit input thereto via a low pass filter, which outputs power at a predetermined voltage;
• a load modulating circuit connected at a connecting point where the rectifier circuit and the low pass filter are connected, which allows data to be transmitted to the power transmitting unit by altering power receiving-side impedance;
• and
• the load modulating circuit changes the power receiving-side impedance based upon strain data detected via the torque measuring strain gauge.