US Patent 7894158 Magnetic disk apparatus

An embodiment of a magnetic disk apparatus in accordance with the present invention includes a magnetic recording medium, a magnetic head assembly having a magnetic head which reads and writes data on the magnetic recording medium, and a motor coil assembly rotationally driving a spindle motor rotation body, in which plural motor coils are arranged on a circumference around the rotation center of the spindle motor rotation body so that intervals in the circumferential direction are equal, in a stator base surrounding a periphery of the spindle motor rotation body and having a shape in which a prescribed moving locus portion of at least the magnetic head assembly is cut out.