Digital output rotational position detection device

A rotational position detection device comprising:

• stator means having a plurality of primary poles arranged in a predetermined arrangement, a secondary pole, primary coils being wound on respective primary poles and a secondary coil being wound on the secondary pole, said poles having end portions;
• rotor means of such configuration as to oppose the end portions of the respective primary poles and the secondary pole with gaps therebetween, change reluctance of magnetic paths passing the respective primary poles in accordance with a rotational position and receive a rotational movement or displacement by rotation which is an object of detection from outside;
• a clock pulse generator;
• reference AC signal generation means for generating reference AC signals having a predetermined frequency and being out of phase with each other in response to a clock generated by said clock pulse generator, said reference AC signal generation means comprising a counter for counting said clock pulse signal and a circuit responsive to an output of the counter to produce said plural reference AC signals;
• means for exciting each of said primary coils on said poles with any one of reference AC signals, each pole excitation signal being out of phase with the excitation signals of adjacent poles by a predetermined electrical angle and thereby producing in the secondary coil an output signal resulting by phase shifting the reference AC signals in accordance with the rotational position of said rotor means;
• and

A digital angular position detection device having:

• a plurality of poles with primary coils wound thereon and excited by out-of-phase signals derived from a clock pulse source and having secondary coils wound on said poles in association with said primary coils to produce an output signal,
• a rotor means receiving a rotational movement or displacement by rotation such that the reluctance change of magnetic paths passing the respective poles varies in accordance with the rotational position of said rotor means, said rotational movement or displacement being an object of detection;
• and
• a phase difference detection circuit comprising:
• a counter incremented in synchronization with said clock pulses,
• a means for initializing the count of said counter in response to a predetermined reference point of one of said exciting signals, and
• a means for outputting the count of said counter at a predetermined point of the output signal, the digital output thereby directly representing the rotational angle of the rotor means in predetermined incremental units.

A digital angular position detection device having:

• a plurality of poles with primary coils wound thereon and excited by out-of-phase signals derived from a clock pulse source and having secondary coils wound on said poles in association with said primary coils to produce an output signal,
• a rotor means receiving a rotational movement or displacement by rotation such that the reluctance change of magnetic paths passing the respective poles varies in accordance with the rotational position of said rotor means, said rotational movement or displacement being an object of detection;
• said clock pulse source comprising:
• a clock pulse generator,
• a counter for counting clock pulses generated by said clock pulse generator, and
• a circuit responsive to an output of the counter to produce said out-of-phase signals;
• and
• a phase difference detection circuit for sampling the count of said counter at a predetermined point of the output signal produced by the secondary coils, the digital count thereby directly representing the rotational angle of the rotor means in predetermined incremental units.