Magnetic core, winding with magnetic core, rotary electric machine, and brushless motor

A magnetic core comprising:

• a back yoke portion having a first upper surface and a first lower surface aligned in an up-down direction;
• a tooth distal end portion having a second upper surface and a second lower surface aligned in the up-down direction;
• and
• a tooth portion extending in the up-down direction and having an upper end in contact with the first lower surface and a lower end in contact with the second upper surface, the tooth portion constructed to have a winding portion of a conductor wound around the tooth portion as viewed in the up-down direction,
• wherein an outer edge of the back yoke portion viewed in the up-down direction surrounds an outer edge of the tooth distal end portion viewed in the up-down direction,
• the outer edge of the tooth distal end portion viewed in the up-down direction surrounds an outer edge of the tooth portion viewed in the up-down direction, and
• the magnetic core has at least one structure of:
• (A) one or more first protrusions protruding from the first lower surface, and
• (B) one or more second protrusions protruding from the second upper surface.