Abstract: A rotor (10) for a synchronous motor includes a plurality of permanent magnets (14) arranged at generally equal intervals around a shaft (12), and a plurality of core members (16) arranged around the shaft (12) while holding each permanent magnet (14) therebetween in a circumferential direction, so as to constitute magnetic poles. Each core member (16) has a symmetrical plane (S) involving a center axis (0) of the shaft (12), and is provided with a rod insertion hole (20) axially passing through the core member so as to involve the symmetrical plane (S) at the generally center of the core member. A rod member (22) is inserted into each rod insertion hole (20).

Abstract: A drive control method for a variable reluctance type motor capable of improving the motor efficiency by preventing generation of a disturbance torque. In function generators (8A to 8C) of a controller for embodying the method, the motor rotation direction and the motor driving mode are determined based on the generation order of A- and B-phase feedback pulses from a pulse coder (7) and the sign of a torque command (Tc) from a speed loop compensation circuit (1), and, on the basis of the determination results, either one of four excitation patterns is selected. Function signal values corresponding to actual motor electrical angles (.theta.) are generated from the function generators in accordance with the selected excitation pattern, and excitation of individual phases of the motor (6) is controlled by power amplifiers (4A to 4C) which respond to voltage commands derived based on these function signal values.

Abstract: This invention determines the configurations of a rotor (10) and a stator (12) and conductance periods and conductance phases of the conductance currents to obtain a smooth rotation of a variable reluctance motor as an AC servo motor. When the number of phases of a motor is m, the number of salient poles (R.sub.j) of a rotor (10) is an integer n, and the number of salient poles (S.sub.k) of a stator (12 ) is r.multidot.m, n is a whole multiple of r, and where the configuration of the stator salient pole (S.sub.k) is rectangular and the configuration of the rotor salient pole (R.sub.j) is sinusoidal, AC sine wave currents shifted by 2n.pi./(r.multidot.m) each and having two times as large a period as that of a magnetic permeance fluctuation caused by a rotation of the rotor (10), are conducted to the phases of the motor.

Abstract: In an optical rotary encoder which detects the angle of rotation of a rotary shaft by detecting the ray of light transmitting through an angle detection pattern formed on a rotary disc coupled to the rotary shaft, a deflection detection pattern (20b) is disposed on the rotary disc separately from the angle detection pattern and the direction and magnitude of deflection of the rotary shaft with respect to the center of a bearing is detected by detecting the change in the quantity of light passing through the deflection detection pattern (20b). The angle of rotation thus detected is corrected to the angle of rotation around the axis of the rotary shaft.