| 摘要 |
The rotational torque of an electromagnetic actuator having a stator and rotor, such as a stepping motor, is increased. The electromagnetic actuator includes a rotor ( 30 ) having multiple magnetic poles (Nr<SUB>1</SUB>, Nr<SUB>2</SUB>, Nr<SUB>3</SUB>, Nr<SUB>4</SUB>, Nr<SUB>5</SUB>, Sr<SUB>1</SUB>, Sr<SUB>2</SUB>, Sr<SUB>3</SUB>, Sr<SUB>4</SUB>, Sr<SUB>5</SUB>) on a circumferential surface ( 31 ) and a plurality of stators ( 10, 20 ) in an electromagnet form. The stator ( 10, 20 ) has a pair of magnetic poles ( 13, 14, 23, 24 ) facing the circumferential surface ( 31 ) of the rotor ( 30 ), and an auxiliary yoke ( 40, 50 ) made of a soft magnetic material member extending in a circumferential direction (A) over an angular range (gamma 1, gamma2 ) larger than a spread angle (alpha) of the magnetic poles (Nr, Sr) of the rotor ( 30 ) in the circumferential direction (A) is provided between the pair of magnetic poles ( 13, 14, 23, 24 ).
|
