Thrust magnetic bearing device

A thrust magnetic bearing device comprising:

• a thrust disc fixed to a rotating body;
• and
• a pair of electromagnets provided so as to sandwich the thrust disc and be spaced apart from the thrust disc in a direction along a rotation axis, each of the pair of electromagnets including:
• a coil wound around the rotation axis of the rotating body;
• and
• a ring-shaped core accommodating the coil, the core including:
• an outside outer peripheral surface that is a radially outer surface;
• an outside inner peripheral surface that is a radially inner surface;
• an outside opposing surface opposed to the thrust disc;
• an outside non-opposing surface located at an opposite side of the outside opposing surface in the direction along the rotation axis;
• an inside outer peripheral surface opposed to the radially outer surface of the coil;
• an inside inner peripheral surface opposed to the radially inner surface of the coil;
• an inside opposing surface opposed to a surface of the coil located close to the thrust disc;
• an inside non-opposing surface located at an opposite side of the inside opposing surface across the coil;
• and
• a slit which is located at at least one circumferential position of the core and extends in a radial direction from the outside outer peripheral surface as a starting point toward a center of the core, the slit being disposed in a range including at least the inside outer peripheral surface and excluding all of the outside opposing surface directly facing the thrust disc and a portion of the inside opposing surface corresponding to the thrust disc.