Multi-shaft driving apparatus and fluid rotary apparatus

In a fluid rotary apparatus comprising:

• a plurality of rotors accommodated in a housing;
• a plurality of shafts each for rotating one of the rotors to be synchronously rotated;
• and
• a fluid drawing opening formed in the housing and a fluid discharge opening formed therein;
• wherein the volume change of a space formed by the rotors and the housing is utilized to draw and discharge fluid,
• the improvement comprising:
• a plurality of motors each for rotating one of a plurality of the shafts to be synchronously rotated;
• an encoder, provided for each rotor, for detecting the rotational state of the shafts;
• a pulse generator for generating a pulse signal for rotating the shafts;
• and
• a motor control circuit, provided for each motor, for inputting the pulse signals from the pulse generator and a pulse signal detected by the encoder and used as a feedback signal to control the synchronization of the shafts, the motor control circuit having a PLL controller for performing a PLL control operation and a rotational angle phasing controller for performing a rotational angle phasing operation;
• and further comprising vacuum setting means for setting an amount of vacuum in a discharge space and vacuum detecting means for detecting the amount of vacuum therein so that the frequency of the pulse signal from the pulse generator for rotating the shafts is varied according to a difference between the set amount of vacuum and the detected amount of vacuum.

In a fluid rotary apparatus comprising:

• a plurality of rotors accommodated in a housing;
• a plurality of shafts each for rotating one of the rotors to be synchronously rotated;
• and
• a fluid drawing opening formed in the housing and a fluid discharge opening formed therein;
• wherein the volume change of a space formed by the rotors and the housing is utilized to draw and discharge fluid,
• the improvement comprising:
• a plurality of motors each for rotating one of a plurality of the shafts to be synchronously rotated;
• an encoder, provided for each motor, for detecting the rotational state of the shafts;
• a pulse generator for generating a pulse signal for rotating the shafts;
• and
• a motor control circuit, provided for each motor, for inputting the pulse signals from the pulse generator and a pulse signal detected by the encoder and used as a feedback signal to control the synchronization of the shafts, the motor control circuit having a PLL controller for performing a PLL control operation and a rotational angle phasing controller for performing a rotational angle phasing operation;
• wherein in the motor control circuit;
• a rotational angle phasing control loop is generated to perform the rotational angle phasing operation by the rotational angle phasing controller so as to synchronously rotate the shafts at a rise time or a fall time, and
• a steady control loop is generated to perform the PLL control operation by the PLL controller at a steady state after the rise time and before the fall time.