Patent ID: 7294946

Claim:
A dynamic pressure gas bearing motor, in which a cylindrical support shaft ( 2 ) is mounted upright on a mounting base ( 1 ), a closed-end cylindrical motor rotation body ( 3 ) is fitted on the support shaft ( 2 ) to enclose the outer periphery thereof at the top and on the side with clearance, a rotor magnet ( 5 ) is provided to the motor rotation body ( 3 ) or a member attached to the motor rotation body ( 3 ), a set of stator coils ( 4 ) is provided concentrically with the support shaft ( 2 ) and facing the rotor magnet ( 5 ), the motor rotation body ( 3 ) is supported by a radial dynamic pressure gas bearing ( 6 ) and a thrust dynamic pressure gas bearing ( 7 ) formed by the clearance, wherein the top surface of the support shaft ( 2 ) has a downward recession, the motor rotation body ( 3 ) has a protruded part ( 3 a ) facing the recession ( 2 a ) of the support shaft ( 2 ) and fitted therein with clearance, the radial dynamic pressure gas bearing ( 6 ) is formed by the inner periphery of the motor rotation body ( 3 ) and the outer periphery of the support shaft ( 2 ), the thrust dynamic pressure gas bearing ( 7 A) is formed by the protruded part ( 3 a ) of the motor rotation body ( 3 ) and the recession ( 2 a ) of the support shaft ( 2 ), the thrust dynamic pressure gas bearing ( 7 A) is provided below the top end of the radial dynamic pressure gas bearing ( 6 ), and clamping screw holes ( 3 c ) for holding a disk or a magnetic recording medium are formed in the top wall ( 3 b ) of the motor rotation body ( 3 ) above the recession ( 2 a ) of the support shaft ( 2 ).