Abstract:
A hub for a disk drive assembly including an upper member formed of a first material; and a lower member formed from a second material that supports and reinforces the upper member. The second material has a rigidity greater than the rigidity of the first material. Additionally, a disk drive assembly may be performed by combining a hub, a disk media mounted to the hub and a clamping mechanism attached to the hub and providing a clamping force to the disk media.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. provisional application No. 61/857,983, filed Jul. 24, 2013, the disclosure of which is hereby incorporated by reference. 
    
    
     FIELD 
     The present disclosure relates generally to information storage devices and, in particular, to a motor hub flange for an information storage device. 
     BACKGROUND 
     Disk drives frequently include a spindle motor, one or more disk media (henceforth “disks”), and one or more clamping elements. In currently shipping hard drives, the disks are clamped against a support flange on the spindle motor. Sometimes, this clamping force is sufficient to cause the flange to deform the flat disk shape. This effect may be combated by increasing the thickness of the motor hub flanges such that they are thick enough to minimize these affects to manageable levels. However, increasingly smaller disk drive design requirements result in a pressure to reduce the Z-height of all components, including the motor hub flanges such that increasing the thickness of the motor hub flanges is becoming less feasible. 
     Implementations of the present application may include a motor hub flange providing a reinforcing portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A general architecture that implements the various features of the disclosure will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate implementations of the disclosure and not to limit the scope of the disclosure. Throughout the drawings, reference numbers are reused to indicate correspondence between referenced elements. 
         FIG. 1  illustrates a disk drive which may incorporate a hub flange according to one or more implementations of the present application. 
         FIG. 2  illustrates a hub according to a related art design. 
         FIG. 3  illustrates a hub according to a first implementation of the present application. 
         FIG. 4  illustrates a hub according to a second implementation of the present application. 
         FIG. 5  illustrates a hub according to a third implementation of the present application. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a disk drive  100  is illustrated which may incorporate a hub flange according to one or more implementations. The disk drive  100  comprises a hub  102  ( 300 ,  400 ,  500  in  FIGS. 3-5 ), a disk  104  physically contacting and supported by at least one mounting surface (not labeled in  FIG. 1 ,  325 ,  425 ,  525  in  FIGS. 3-5  respectively) of the hub  102 , and a head  106  operable to write to and read from the disk  104 . The hub  102  may comprises a substantially cylindrical portion  108  which define a longitudinal axis and a mounting surface substantially normal to the longitudinal axis, the mounting surface extending radially outward. 
     As illustrated in  FIG. 1 , a disk drive  100  comprises a magnetic disk drive, and the structures and methods described herein will be described in terms of such a disk drive. However, these structures and methods may also be applied to and/or implemented in other disk drives, including, e.g., optical and magneto-optical disk drives. 
     The disks  104  may comprise any of a variety of magnetic or optical disk media having a substantially concentric opening  114  defined there through. Of course, in other embodiments, the disk drive  100  may include more or fewer disks. For example, the disk drive  100  may include one disk or it may include two or more disks. The disks  104  each include a disk surface  116 , as well as an opposing disk surface not visible in  FIG. 1  above. In one embodiment, the disk surfaces  116  comprise a plurality of generally concentric tracks for storing data. 
     As illustrated, the hub  102  may be coupled to and support the disks  104 . Specifically, the hub  102  may provide a flange (Not labeled in  FIG. 1 , shown in  FIGS. 3-5  below). The hub  102  may also be rotatably attached to a motor base  118  of the disk drive  100 , and may form one component of a motor  120  (e.g., a spindle motor). The motor  120  and the hub  102  may be configured to rotate the disks  104  about the longitudinal axis L. 
     Further, a disk clamp  140  may be coupled to the hub  102  to provide a downward clamping force to the disks  104 . Specifically, the disk clamp  140  may be positioned above the disks  104  and attached to an upper surface of the hub  102 . The interaction of the disk clamp  140  and the hub  102  to provide the downward clamping force is discussed in more detail below. 
     The disk drive  100  may further include a cover  122 , which, together with the motor base  118 , may house the disks  104  and the motor  120 . The disk drive  100  may also include a head stack assembly (“HSA”)  124  rotatably attached to the motor base  118 . The HSA  124  may include an actuator  126  comprising an actuator body  128  and one or more actuator arms  130  extending from the actuator body  128 . The actuator body  128  may further be configured to rotate about an actuator pivot axis. 
     One or two head gimbal assemblies (“HGA”)  132  may be attached to a distal end of each actuator arm  130 . Each HGA  132  includes a head  106  operable to write to and read from a corresponding disk  104 . The HSA  124  may further include a coil  134  through which a changing electrical current is passed during operation. The coil  134  interacts with one or more magnets  136  that are attached to the motor base  118  to form a voice coil motor (“VCM”) for controllably rotating the HSA  124 . 
     The head  106  may comprise any of a variety of heads for writing to and reading from a disk  104 . In magnetic recording applications, the head  106  may include an air bearing slider and a magnetic transducer that includes a writer and a read element. The magnetic transducer&#39;s writer may be of a longitudinal or perpendicular design, and the read element of the magnetic transducer may be inductive or magneto resistive. In optical and magneto-optical recording applications, the head may also include a mirror and an objective lens for focusing laser light on to an adjacent disk surface. 
     The disk drive  100  may further include a printed circuit board (“PCB”) (not shown). The PCB may include, inter alia, a disk drive controller for controlling read and write operations and a servo control system for generating servo control signals to position the actuator arms  130  relative to the disks  104 . 
       FIG. 2  below illustrates a hub  200  according to a related art design. As shown, the hub  200  includes a body portion  215  having a substantially cylindrical shape and a support flange  220 . The substantially cylindrical shape of the body portion  215  of the hub may generally be sized to fit through the concentric opening  114  of a disk  104 , such as those shown in  FIG. 1 . Additionally, the upper surface of the support flange  220  provides a disk mounting surface  225  configured to contact and support a disk  104  such as those shown in  FIG. 1 . Frequently, the hub  200  is formed from a material that can be machined or molded relatively easily, such as aluminum or plastic. In  FIG. 2 , the hub is shown as being machined from aluminum. Additionally, a back iron member  210  configured to block the magnetic flux of the motor from passing through the hub  200  is disposed radially inward of the hub  200 . To provide this magnetic shielding, the back iron member  210  is formed of a ferromagnetic material such as iron or steel as shown in  FIG. 2 . 
     As discussed above, related art hard drives have the disks  104  clamped against the support flange  220  on the spindle motor. As the support flange  220  is formed from a material selected to be more easily machined or molded, this clamping action force can be sufficient to cause the support flange to deform the flat disk shape in an undesirable fashion. To combat this effect the motor hub flanges are designed to be thick enough to minimize these affects to manageable levels. However, increasing thickness of the support flange is not always feasible. 
       FIG. 3  illustrates a hub  300  according to a first implementation of the present application. As illustrated, the hub  300  includes an upper member  305  and a lower member  310 . The upper member includes a body portion  315  having a substantially cylindrical shape and a disk support portion or flange  320 . The disk support portion or flange  320  extends radially outward from the body portion  315  a length L 2 . 
     The substantially cylindrical shape of the body portion  315  of the hub is generally sized to fit through the concentric opening  114  of a disk  104 , such as those shown in  FIG. 1 . Additionally, the upper surface of the disk support portion or flange  320  provides a disk mounting surface  325  configured to contact and support a disk  104 , such as those shown in  FIG. 1 . 
     In this implementation, the upper member  305  is formed from aluminum, but in other implementations, the upper member  305  may be formed of other metal material(s) or non-metallic material(s) that that can be machined or molded relatively easily, such as aluminum or plastic. 
     The hub  300  also includes a lower member  310  comprising a main portion  330  and a support portion or flange  335 . As illustrated, the support portion or flange  335  is configured to extend radially outward from a lower portion of the main portion  330  of the lower member  310  to support the disk support portion or flange  320  of the upper member  305 . In some implementations, the upper surface  340  of the lower member  310  is bonded to an underside  345  of the upper member  305  to form the hub  300 . The bonding of the lower member  310  to the upper member  305  to form the hub  300  may be done using a variety of techniques including bonding with adhesive, welding, press fitting or any other technique for rigidly attaching components as would be apparent to a person of ordinary skill in the art. 
     As illustrated, the support portion or flange  335  extends a length L 1  radially outward from the main portion  330 . In this implementation, the length L 1  is such that the support portion or flange  335  extends along the entire length L 2  of the disk support portion or flange  320 . In alternative embodiments, the support portion or flange  335  may only extend along only a portion of the length L 2  of the disk support portion or flange  320  or may extend beyond the length L 2 . 
     In this implementation, the lower member  310  is formed of steel, but in other implementations the lower member  310  may be formed of other materials having a rigidity greater than the rigidity of the upper member  305 . For example, if the upper member  305  is formed from aluminum or plastic, the lower member  310  may be formed from metal(s) or non-metallic material(s) having a rigidity greater than the rigidity of aluminum or plastic, such as carbon fiber, titanium etc. 
     Additionally, some implementations the lower member  310  can be formed of a ferromagnetic material, such as steel. In such implementations, the lower member  310  can function as a back iron and provide magnetic shielding configured to block the magnetic flux of the motor from passing through the hub  300 . However, in other embodiments, the lower member  310  may be formed separate from a back iron piece (not shown herein). 
       FIG. 4  illustrates a hub  400  according to a second implementation of the present application. As illustrated, the hub  400  includes an upper member  405  and a lower member  410 . The upper member  405  includes a body portion  415  having a substantially cylindrical shape and a disk support portion or flange  420 . The disk support portion or flange  420  extends radially outward from the body portion  415  a length L 2 . 
     The substantially cylindrical shape of the body portion  415  of the hub may generally be sized to fit through the concentric opening  114  of a disk  104 , such as those shown in  FIG. 1 . Additionally, the upper surface of the disk support portion or flange  420  provides a disk mounting surface  425  configured to contact and support a disk  104 , such as those shown in  FIG. 1 . 
     In this implementation, the upper member  405  is formed from aluminum, but in other implementations, the upper member  405  may be formed of other metal material(s) or non-metallic material(s) that that can be machined or molded relatively easily, such as aluminum or plastic. 
     The hub  400  also includes a lower member  410  comprising a main portion  430  and a support portion or flange  435 . As illustrated, the support portion or flange  435  is configured to extend radially outward from a lower portion of the main portion  430  of the lower member  410  to support the disk support portion or flange  420  of the upper member  405 . In some implementations, the upper surface  440  of the lower member  410  is bonded to an underside  445  of the upper member  405  to form the hub  400 . The bonding of the lower member  410  to the upper member  405  to form the hub  400  may be done using a variety of techniques including bonding with adhesive, welding, press fitting or any other technique for rigidly attaching components as would be apparent to a person of ordinary skill in the art. 
     As illustrated, the support portion or flange  435  extends a length L 1  radially outward from the main portion  430 . In this implementation, the length L 1  is such that the support portion or flange  435  extends along only a portion of the entire length L 2  of the disk support portion or flange  420 . A lower, outer portion  450  of the upper member is disposed radially outward of the radially outer edge  455  of the support portion or flange  435  of the lower member  410 . In alternative embodiments, the support portion or flange  435  may extend along the entire length L 2  of the disk support portion or flange  420  of the upper member  405  or may extend beyond the radially outer-most portion  460  of the upper member  405 . 
     In this implementation, the lower member  410  is formed of steel, but in other implementations the lower member  410  may be formed of other materials having a rigidity greater than the rigidity of the upper member  405 . For example, if the upper member  405  is formed from aluminum or plastic, the lower member  410  may be formed from metal(s) or non-metallic material(s) having a rigidity greater than the rigidity of aluminum or plastic, such as carbon fiber, titanium etc. 
     Additionally, in some implementations, the lower member  410  can be formed of a ferromagnetic material, such as steel. In such implementations, the lower member  410  can function as a back iron and provide magnetic shielding configured to block the magnetic flux of the motor from passing through the hub. However, in other embodiments, the lower member  410  may be formed separate from a back iron piece (not shown herein). 
       FIG. 5  illustrates a hub  500  according to a third implementation of the present application. As illustrated, the hub  500  includes an upper member  505  and a lower member  510 . Like the above discussed implementations, the upper member  505  includes a body portion  515  having a substantially cylindrical shape. The substantially cylindrical shape of the body portion  515  of the hub  500  is generally sized to fit through the concentric opening  114  of a disk  104 , such as those shown in  FIG. 1 . However, unlike the implementations discussed above, the upper member  505  does not include a disk support portion or flange. 
     In this implementation, the upper member  505  is formed from aluminum, but in other implementations, the upper member  505  may be formed of other metal materials or a non-metallic material that that can be machined or molded relatively easily, such as aluminum or plastic. 
     The hub  500  also includes a lower member  510  comprising a main portion  530  and a disk support portion or flange  535 . As illustrated, the disk support portion or flange  535  is configured to extend radially outward from a lower portion of the main portion  530  of the lower member  510 . Additionally, the upper surface of the disk support portion or flange  535  provides a disk mounting surface  525  configured to contact and support a disk  104 , such as those shown in  FIG. 1 . 
     In some implementations, the upper surface  540  of the lower member  510  is bonded to an underside  545  of the upper member  505  to form the hub  500 . The bonding of the lower member  510  to the upper member  505  to form the hub  500  may be done using a variety of techniques including bonding with adhesive, welding, press fitting or any other technique for rigidly attaching components as would be apparent to a person of ordinary skill in the art. 
     As illustrated, the disk support portion or flange  535  extends a length L 1  radially outward from the main portion  530 . In this implementation, the length L 1  is such that the disk support portion or flange  535  extends beyond the entire length of the body portion  515  of the upper member  505 . As discussed above in alternative implementations, the length L 1  of the disk support portion or flange  535  of the lower member  510  may vary and be shorter than or the same length as a component of the upper member  505 . 
     In this implementation, the lower member  510  is formed of steel, but in other implementations the lower member  510  may be formed of other materials having a rigidity greater than the rigidity of the upper member  505 . For example, if the upper member  505  is formed of aluminum or plastic, the lower member  510  may be formed from metal(s) or non-metallic material(s) having a rigidity greater than the rigidity of aluminum or plastic such as carbon fiber, titanium etc. 
     Additionally, in some implementations the lower member  510  can be formed of a ferromagnetic material, such as steel. In such implementations, the lower member  510  can function as a back iron and provide magnetic shielding configured to block the magnetic flux of the motor from passing through the hub. However, in other embodiments, the lower member  510  may be formed separate from a back iron piece (not shown herein). 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the protection. Indeed, the novel methods and apparatuses described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the protection.