Abstract:
Methods in accordance with the present invention can eliminate cumbersome and potentially contaminating methods for connecting a bearing assembly with an actuator assembly. One such assembly comprises a bearing assembly with a threaded base for insertion into a bore, wherein the bore includes threads for engaging the threaded base of the bearing assembly, eliminating the contamination associated with such methods as glueing. The bearing assembly is designed such that it can be disconnected from the actuator assembly for rework without damaging or contaminating the actuator assembly or bearing assembly. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Description:
PRIORITY CLAIM  
       [0001]    This application claims priority to the following U.S. Provisional Patent Application:  
         [0002]    U.S. Provisional Patent Application No. 60/437,164, entitled “Method for Seating a Removable Bearing Assembly in a Rotary Actuator Assembly for a Rotatable Media Data Storage Device,” Attorney Docket No. PANA-01034US1, filed Dec. 30, 2002.  
       CROSS-REFERENCED CASES  
       [0003]    This application incorporates by reference all of the following co-pending applications:  
         [0004]    U.S. patent application Ser. No. ______, entitled “Rotary Actuator Assembly for a Rotatable Media Data Storage Device,” Attorney Docket No. PANA-01003US2, filed herewith.  
         [0005]    U.S. patent application Ser. No. ______, entitled “Methods for Assembling or Reworking a Rotary Actuator Assembly for a Rotatable Media Data Storage Device,” Attorney Docket No. PANA-01003US3, filed herewith.  
         [0006]    U.S. patent application Ser. No. ______, entitled “Modular Rotary Actuator Assembly for a Rotatable Media Data Storage Device,” Attorney Docket No. PANA-01028US2, filed herewith.  
         [0007]    U.S. patent application Ser. No. ______, entitled “Methods for Assembling or Reworking a Modular Rotary Actuator Assembly for a Rotatable Media Data Storage Device,” Attorney Docket No. PANA-01028US3, filed herewith.  
         [0008]    U.S. patent application Ser. No. ______, entitled “Methods for Seating a Removable Bearing Assembly in a Rotary Actuator Assembly for a Rotatable Media Data Storage Device,” Attorney Docket No. PANA-01034US2, filed herewith. 
     
    
     
       FIELD OF THE INVENTION  
         [0009]    The present invention relates to actuator assemblies within rotatable media data storage as for example magnetic or optical hard disk drive technology.  
         BACKGROUND OF THE INVENTION  
         [0010]    Computer systems are fundamentally comprised of subsystems for storing and retrieving information, manipulating information, and displaying information. Nearly all computer systems today use optical, magnetic or magneto-optical storage media to store and retrieve the bulk of a computer system&#39;s data. Successive generations of ever more powerful microprocessors, and increasingly complex software applications that take advantage of these microprocessors, have driven the storage capacity needs of systems higher and have simultaneously driven read and write performance demands higher. Magnetic storage remains one of the few viable technologies for economically storing large amounts of information with acceptable read and write performance.  
           [0011]    Market pressures place ever greater demands on hard disk drive manufacturers to reduce drive costs. To maintain market advantage, new hard disk drive designs typically incorporate greater efficiency in device operating tolerances or manufacturability.  
           [0012]    There are basic components common to nearly all hard disk drives. A hard disk drive typically contains one or more disks clamped to a rotating spindle, ahead for reading or writing information to the surface of each disk, and an actuator assembly utilizing linear or rotary motion for positioning the head for retrieving information or writing information to a location on the disk. A rotary actuator is a complex assembly that couples the head to a pivot point that allows the head to sweep across the surface of the rotating disk. The assembly typically couples the head to a flexible member called a suspension, which is then coupled to the pivotally mounted actuator assembly.  
           [0013]    The pivoting motion of a rotary actuator is achieved with minimal friction by connecting the actuator assembly with a bearing assembly such that the actuator assembly does not slip relative to the pivoting portion of the bearing assembly. Common methods of connecting an actuator assembly with a bearing assembly are typically cumbersome and risk contamination, or are not suitable for smaller bearing assembly diameters 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0014]    Further details of embodiments of the present invention are explained with the help of the attached drawings in which:  
         [0015]    [0015]FIG. 1A is an exploded view of a typical hard disk drive utilizing a bearing assembly in accordance with one embodiment of the present invention.  
         [0016]    [0016]FIG. 1B is an illustration of the rotary motion of an actuator assembly of FIG. 1A across the surface of a disk.  
         [0017]    [0017]FIG. 2 illustrates the actuator assembly of FIG. 1A with a bearing assembly in accordance with one embodiment of the invention removed.  
         [0018]    [0018]FIG. 3 is a cross-sectional view of a portion of the actuator assembly and the bearing assembly of FIG. 2.  
         [0019]    [0019]FIG. 4 is an exploded view of an actuator assembly comprised of arm plates and a bearing assembly in accordance with one embodiment of the invention. 
     
    
     DESCRIPTION  
       [0020]    [0020]FIG. 1 is an exploded view of a hard disk drive  100  utilizing a bearing assembly in accordance with one embodiment of the present invention. The hard disk drive  100  has a housing  102  which is formed by a housing base  104  and a housing cover  106 . A single disk  120  is attached to the hub of a spindle motor  122 , with the spindle motor  122  mounted to the housing base  104 . The disk  120  can be made of a light aluminum alloy, ceramic/glass or other suitable substrate, with magnetic material deposited on one or both sides of the disk  120 . The magnetic layer has tiny domains of magnetization for storing data transferred through heads. The invention described herein is equally applicable to technologies using other media, as for example, optical media. Further, the invention described herein is equally applicable to devices having any number of disks attached to the hub of the spindle motor. The disks are connected to a rotating spindle  122  (for example by clamping), spaced apart to allow the heads  146  to access the surfaces of each disk  120 , and rotated in unison at a constant or varying rate typically ranging from less than 3,600 RPM to over 15,000 RPM (speeds of 4,200 and 5,400 RPM are common in hard disk drives designed for mobile devices such as laptops).  
         [0021]    The actuator assembly  130  is pivotally mounted to the housing base  104  by a bearing assembly  160  and sweeps an arc, as shown in FIG. 1B, between the inner diameter of the disk  120   a  and the outer diameter of the disk  120   b . Attached to the housing  104  are upper and lower magnet return plates  110  and at least one magnet that together form the stationary portion of the voice coil motor assembly  112 . The voice coil  134  is mounted to the actuator assembly  130  and positioned in the air gap of the voice coil motor  112  which applies a force to the actuator assembly  130  to provide the pivoting motion about the bearing assembly  160 . The voice coil motor allows for precise positioning of the heads  146  along the surface of the disk  120 . The voice coil motor  112  is coupled with a servo system (not shown) to accurately position the head  146  over a specific track on the disk  120 . The servo system acts as a guidance system, using positioning code (for example grey code) read by the head  146  from the disk  120  to determine the position of the head  146  on tracks  124  on the disk  120 . The actuator assembly  130  is shown in FIGS. 1 and 2 to have an overall wedge-shape, but could alternatively have a variety of shapes: for example, the actuator assembly could be rectangular or oblong, or shaped like an arrow.  
         [0022]    The heads  146  read and/or write data to the disks. Each side of a disk  120  can have an associated head  146 , and the heads  146  are collectively coupled to the actuator assembly  130  such that the heads  146  pivot in unison. When not in use, the heads  146  can rest on the stationary disk  120  (typically on an inner portion of the disk that does not contain data) or on a ramp  150  positioned either adjacent to a disk or just over the disk surface.  
         [0023]    [0023]FIG. 2 illustrates an actuator assembly with a bearing assembly in accordance with the present invention removed from the actuator assembly. The actuator assembly  130  comprises amounting block  132  having a solid bore for receiving the bearing assembly  160 . Actuator arms  138  attach to a first end of the mounting block  132 . Each actuator arm  138  can be attached with screws or adhesive, for example, or can be cast or extruded as part of the mounting block  132 . In other embodiments the actuator arm  138  can be an actuator arm plate that includes a circular bore, that when coupled to spacer elements, forms a cylindrical bore designed to receive the bearing assembly  160 . A head suspension assembly  140  is connected with each arm  138 , typically by spot-welding or ball swaging. A voice coil holder  136  is mounted at a second end of the mounting block  132 , and retains a voice coil  134 . The voice coil holder  136  maybe cast as part of a singular block element with the mounting block  132 , adhesively bonded or plastic over-molded onto the mounting block  132 . One of ordinary skill in the art can appreciate the different methods for fastening the voice coil holder  136  to the mounting block  132 .  
         [0024]    The bearing assembly  160  can be connected with the actuator assembly  130  using one of a number of different methods, including: gluing the bearing assembly  160  to the walls of the bore of the mounting block  132 , holding the bearing assembly  160  in position with a snap-ring, attaching the bearing assembly  160  to the bore with a set screw inserted through a hole in the side of the mounting block  132 , or press-fitting the bearing assembly  160  into the bore. Each of these methods has its own associated problems. Gluing the bearing assembly  160  to the walls of the bore is cumbersome, can cause contamination in the hard disk drive and complicates disassembly for rework. Press-fitting the bearing assembly  160  into the bore similarly complicates disassembly for rework. Attaching the bearing assembly  160  to the bore using a snap-ring is cumbersome as well. Fixing the bearing assembly  160  to the bore using a set screw requires sufficient material in both the barrel of the cartridge and the side of the mounting block  132  to support the screw torque. Snap-rings and set screws are not suitable methods of connecting a bearing assembly  160  with a mounting block  132  for smaller hard disk drive form factors. Similarly, gluing and press-fitting are not suitable methods of connecting a bearing assembly  160  with amounting block  132  where proper cleaning and actuator assembly rework are desired.  
         [0025]    As shown in FIG. 2, a bearing assembly  160  in accordance with one embodiment of the present invention has a threaded base  364  and seating flange  362 . FIG. 3 shows a cross-section of the bearing assembly  160  and mounting block  132 . The mounting block  132  includes a threaded bore  366  for receiving the threaded base  364  of the bearing assembly  160 . The mounting block  132  is shown to be a single cast or extruded piece with a solid bore, but alternatively can be machined or comprised of multiple pieces. For example, the mounting block  132  can include a cylindrical bore comprised of arm plates each with a circular bore (as described above and shown in FIG. 4), with at least one arm plate including threads  366  for receiving the threaded base  364  of the bearing assembly  160 .  
         [0026]    As shown in FIG. 3, the bearing assembly  160  can be a cartridge bearing having two sets of ball-bearings  368  between concentric cylinders—one set of ball-bearings  368   b  near the base of the bearing assembly and one set of ball-bearings  368   a  near the top of the bearing assembly. The outer cylinder  372  rotates relatively freely about the inner cylinder  370 . The bearing assembly  160  can be connected with a housing  104  by a rod (not shown) attached to the housing  104  and inserted within the inner cylinder  370 . In other embodiments the bearing assembly  160  may have more than two sets of ball-bearings  368 , or may have one or more sets of roller bearings. In still other embodiments the bearing assembly  160  may use fluid-dynamic bearings.  
         [0027]    The bearing assembly  160  can also include a seating flange  362  for seating and unseating the bearing assembly  160  in the bore of the mounting block  132 . In one embodiment the seating flange  362  is circular, while in other embodiments the seating flange  362  includes a wrenching flat. In still other embodiments the bearing assembly  160  does not have a seating flange  362 .  
         [0028]    The invention described herein is equally applicable to technologies using other read/write devices and other data storage media. For example, a bearing assembly  160  in accordance with the embodiments described herein could be used with a rotary actuator connected with a laser or an atomic probe for writing to a polycrystalline silicon substrate. The invention described herein is equally applicable to unrelated technologies using bearing assemblies. The description and illustrations provided are not intended to limit the invention to data storage technology.  
         [0029]    Methods are also provided for seating a bearing assembly  160  in accordance with embodiments of the present invention. In one such method, the bearing assembly  160  is inserted into the bore of a mounting block  132  of the actuator assembly until threads  364  of the bearing assembly  160  contact threads  366  within the bore. The bearing assembly  160  is rotated such that the threads  364  of the bearing assembly  160  engage the threads  366  of the bore until the bearing assembly  160  is seated within the bore. In other embodiments, the bearing assembly  160  has a wrenching flat for more easily applying torque or rotating the bearing assembly  160 .  
         [0030]    The foregoing description of preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to one of ordinary skill in the relevant arts. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalence.