Overmolded motor hub

Abstract

Accurately formed critical tolerance fit components are provided for fluid dynamic bearing motors, including disc drive memory systems. In an aspect, critical tolerance fit components are molded to a metal insert and include a portion of a hub, a disc seating surface, and a disc locating surface. The insert includes another portion of a hub, a sleeve, or a disc clamp retainer for a novel disc clamp. In an aspect, the plastic component is situated to cause the thermal expansion of the plastic to be restricted by the thermal expansion of a metal insert. Expensive machining of a stamped metal hub is minimized or eliminated by using the molded component portions. Strict component tolerances are provided as needed for perpendicularity relative to motor rotation for seating a disc with accurate flatness, a circumferential surface for centering the disc, and tight parallelism between a disc mounting surface and a center shaft.

1 . In a fluid dynamic bearing motor having a hydrodynamic bearing defined between an inner component and an outer component, wherein the inner component and the outer component are positioned for relative rotation, a method of forming a critical tolerance fit component of the fluid dynamic bearing motor comprising:
 situating an insert in a predetermined orientation in a molding device, wherein the insert is a portion of the fluid dynamic bearing motor;   introducing a raw material into the molding device;   molding the raw material into a predetermined form as defined by a cavity, wherein the predetermined form is the critical tolerance fit component fixed to the insert, and wherein the cavity is at least defined by a surface of the insert and an inside surface of the molding device; and   separating the insert and critical tolerance fit component from the molding device.   
     
     
         2 . The method as in  claim 1 , wherein the insert comprises at least one of a first portion of a hub, a sleeve, and a disc clamp retainer. 
     
     
         3 . The method as in  claim 2 , wherein the cavity is further defined by an opening or a through-hole defined by the first portion of the hub, and wherein the raw material is fixed to the first portion of the hub within the opening or through-hole. 
     
     
         4 . The method as in  claim 1 , wherein the critical tolerance fit component comprises one of a second portion of a hub, a disc seating surface, and a disc locating surface, wherein the second portion of the hub is situated at least one of adjacent to a first portion of a hub, adjacent to a sleeve and adjacent to a disc clamp retainer. 
     
     
         5 . The method as in  claim 2 , wherein the first portion of the hub is stamped from a metal. 
     
     
         6 . The method as in  claim 2 , wherein the raw material is plastic, and the first portion of the hub is steel. 
     
     
         7 . The method as in  claim 6 , wherein the plastic raw material is situated to cause a thermal expansion of the plastic to be restricted by a thermal expansion of the insert. 
     
     
         8 . The method as in  claim 6 , wherein the plastic comprises one of Ultem and poly-phenylene sulfide (PPS). 
     
     
         9 . In a fluid dynamic bearing motor having: (i) a hydrodynamic bearing defined between an inner component and an outer component, wherein the inner component and the outer component are positioned for relative rotation; (ii) a data storage disc attached to one of the inner component and the outer component; and (iii) an actuator supporting a head proximate to the data storage disc for communicating with the data storage disc; a method of forming a critical tolerance fit component of the fluid dynamic bearing motor comprising:
 situating an insert in a predetermined orientation in a molding device, wherein the insert is a portion of the fluid dynamic bearing motor;   introducing a raw material into the molding device;   molding the raw material into a predetermined form as defined by a cavity, wherein the predetermined form is the critical tolerance fit component fixed to the insert, and wherein the cavity is at least defined by a surface of the insert and an inside surface of the molding device; and   separating the insert and critical tolerance fit component from the molding device.   
     
     
         10 . The method as in  claim 9 , wherein the insert comprises at least one of a first portion of a hub, a sleeve, and a disc clamp retainer. 
     
     
         11 . The method as in  claim 10 , wherein the cavity is further defined by an opening or a through-hole defined by the first portion of the hub, and wherein the raw material is fixed to the first portion of the hub within the opening or through-hole. 
     
     
         12 . The method as in  claim 9 , wherein the critical tolerance fit component comprises one of a second portion of a hub, a disc seating surface, and a disc locating surface, wherein the second portion of the hub is situated at least one of adjacent to a first portion of a hub, adjacent to a sleeve and adjacent to a disc clamp retainer. 
     
     
         13 . The method as in  claim 10 , wherein the first portion of the hub is stamped from a metal. 
     
     
         14 . The method as in  claim 10 , wherein the raw material is plastic, and the first portion of the hub is steel. 
     
     
         15 . The method as in  claim 14 , wherein the plastic raw material is situated to cause a thermal expansion of the plastic to be restricted by a thermal expansion of the insert. 
     
     
         16 . The method as in  claim 14 , wherein the plastic comprises one of Ultem and poly-phenylene sulfide (PPS). 
     
     
         17 . A fluid dynamic bearing motor comprising:
 a hydrodynamic bearing defined between an inner component and an outer component, wherein the inner component and the outer component are positioned for relative rotation;   a metal portion of the fluid dynamic bearing motor including at least one of a first portion of a hub, a sleeve, and a disc clamp retainer; and   a plastic portion of the fluid dynamic bearing motor, wherein the plastic portion of the fluid dynamic bearing motor is a critical tolerance fit component fixed to the metal portion of the fluid dynamic bearing motor, wherein the critical tolerance fit component comprises one of a second portion of a hub, a disc seating surface, and a disc locating surface, and wherein the second portion of the hub is situated adjacent to at least one of the first portion of the hub, a sleeve and a disc clamp retainer.   
     
     
         18 . The fluid dynamic bearing motor as in  claim 17 , wherein the plastic portion of the fluid dynamic bearing motor is fixed within an opening or a through-hole defined by the first portion of the hub, 
     
     
         19 . The fluid dynamic bearing motor as in  claim 18 , wherein the plastic portion of the fluid dynamic bearing motor is situated to cause a thermal expansion of the plastic portion of the fluid dynamic bearing motor to be restricted by a thermal expansion of the metal portion of the fluid dynamic bearing motor. 
     
     
         20 . The fluid dynamic bearing motor as in  claim 17 , wherein the plastic portion of the fluid dynamic bearing motor is comprised of one of Ultem and poly-phenylene sulfide (PPS).