Spindle motor assembly with polymeric motor shaft and hub for rotating a data storage disk

A computer disc drive comprising:

• a spindle motor assembly including:
• a polymeric motor shaft having a pattern of pressure generating features,
• a polymeric hub to support a rotating disc,
• a stator disposed in an internal cavity defined by the hub, and
• a snap-in retainer molded to the motor shaft to hold the hub in place,
• wherein a surface of the polymeric hub and an opposing surface of the polymeric motor shaft form a hydrodynamic bearing, and wherein during operation of the disc drive, the journal bearing and pressure generating features create a pressure gradient in a gap between the surface of the motor shaft and the opposing surface of the hub.

A method of assembling a spindle motor assembly for a computer disc drive, the method comprising:

• positioning a hub over a motor shaft;
• pressing the hub downward so that an extension on the hub contacts a snap-in retainer molded to the motor shaft;
• and
• allowing the snap-in retainer to spring back to hold the hub in place.