Patent ID: 7511919

Claim:
A magnetic disk apparatus comprising: a magnetic disk on which data is recorded while the magnetic disk is driven; a hub supporting the magnetic disk there around rotatably; a clamp which holds the magnetic disk with an annular rotor magnet; a magnetic head for recording data on and replaying the data from the magnetic disk while the magnetic disk is rotated; the annular rotor magnet disposed on and around an outer circumferential surface of the hub; an annular stator disposed around an outer circumferential surface of the annular rotor magnet; an elastic member interposed between the annular rotor magnet and an under surface of the magnetic disk and composed of a material having a rigidity lower than that of the clamp; and a spacer member separate from the clamp interposed between the elastic member and the under surface of the magnetic disk, wherein the clamp is coupled to the hub such that the upper surface of the magnetic disk and an upper surface of the hub are on the same surface.