Abstract:
In certain embodiments, an apparatus includes a basedeck for a hard disc drive. The basedeck includes an interior surface for supporting disc drive components and an exterior surface. The basedeck includes a cavity in either the exterior surface or interior surface. The cavity includes at least two pads for supporting an electrical connector.

Description:
SUMMARY 
     In certain embodiments, an apparatus includes a basedeck for a hard disc drive. The basedeck includes an interior surface for supporting disc drive components and an exterior surface. The basedeck includes a cavity in either the exterior surface or interior surface. The cavity includes at least two pads for supporting a conductive bulkhead. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  provides an isometric exploded view of a hard disk drive, in accordance with certain embodiments of the present disclosure. 
         FIG. 2  provides a partial, isometric view of a bottom of a hard disk drive base, in accordance with certain embodiments of the present disclosure. 
         FIG. 3  provides a side view of a cavity in a hard disk drive base, in accordance with certain embodiments of the present disclosure. 
         FIGS. 4 and 5  provide top views of cavities in a hard disk drive base, in accordance with certain embodiments of the present disclosure. 
         FIGS. 6 and 7  provide partial, isometric views of a bottom of a hard disk drive base, in accordance with certain embodiments of the present disclosure. 
         FIG. 8  provides a partial side view of a hard disk drive base and conductive bulkhead, in accordance with certain embodiments of the present disclosure. 
         FIGS. 9 and 10  provide partial, isometric views of a bottom of a hard disk drive base, in accordance with certain embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Data storage devices can be filled with air or a lower density gas, such as helium, and sealed to control and maintain a storage device&#39;s internal environment. Sealing mitigates or prevents leakage of internal gases from within the storage device. One potential source of leaks in a data storage device involves areas around bulkheads, which facilitate transmission of electrical signals to and from the storage device. Bulkheads can be coupled or joined to storage devices by, among other things, fasteners, gaskets, solder, welds, adhesives or a combination of such. 
     When an adhesive is used to couple or join a bulkhead to a storage device, the adhesive is applied in the area between the bulkhead and storage device. The adhesive can be a source of leakage. Applicants have found that leak rates of adhesive joints are somewhat inversely proportional to a thickness of the adhesive. Moreover, structural integrity of the adhesive joint is somewhat proportional to the thickness of the adhesive. Certain embodiments of the present disclosure are accordingly directed to systems, devices, and methods for controlling dimensions of adhesives. 
       FIG. 1  shows a hard disk drive  100  including a basedeck  102 , top cover  104 , and various data storage components. The basedeck  102  and top cover  104  can form a housing for components such as magnetic disks  106  for recording and storing data, a spindle motor  108  to rotate the disk  106 , a head stack assembly (HSA)  110 , and an actuator  112 . The HSA  110  includes a magnetic head  114 . The actuator  112  is coupled to the magnetic head  114  and moves the magnetic head  114  by operation of a voice coil motor to position the magnetic head  114  over the rotating disk  106 . The magnetic head  114  records data to or reproduces data from the disk  106 . That data is transmitted to a printed circuit board (PCB) by a flexible printed circuit  116  via a conductive bulkhead  118 . The PCB is positioned at an outer portion of the base  102 . 
     A through hole  120  in the basedeck  102  enables the flexible printed circuit  116  to connect to the PCBA positioned outside the base  102  via a conductive bulkhead  118 . The through hole  120  and area around the bulkhead  118  can be a potential source of leaks of the internal gas atmosphere of the hard disk drive  100 . Accordingly, the present disclosure features methods and devices for mitigating gas leakage around through holes and bulkheads. 
       FIGS. 2 and 3  partially show a base  200  of a hard disk drive. The bottom surface  202  of the base  200  includes a cavity  204 . Internal to the cavity  204  are pads  206  shown as being positioned in corners of the cavity  204  and protruding from a bottom surface  208  of the cavity  204 . The bottom surface  208  defines a through hole  210 . The through hole  210  extends from the bottom surface  208  of the cavity  204  to the base&#39;s  200  interior surface, which houses and supports disk drive components like a spindle motor, voice coil motor, and an actuator. The figures in the present disclosure show cavities in the bottom surface of the base, but the disclosure is not so limited. Applicants recognize that cavities can be featured in the interior surface. 
       FIG. 2  shows a conductive bulkhead  212 , which can be positioned in the cavity  204 . The conductive bulkhead can be made of a number of materials, including a low temperature co-fired ceramic (LTCC). When made of an LTCC material, the conductive bulkhead  212  is substantially impermeable to helium or other low density gases. The bulkhead  212  includes conductors  214  that enable transmission of electrical signals to and from the hard disk drive. When using an adhesive  216  to bond or join the bulkhead  212  to the base  200 , the adhesive joint is the primary leak path around the bulkhead  212 . 
     The bulkhead  212  is joined to the base by first applying a bead or line (e.g., bond line) of adhesive to the bottom surface  208  of the cavity  204 . When applied, the adhesive is in an uncured state. The bulkhead  212  is damped or positioned in the cavity  204  while the adhesive cures. The clamping or positioning of the bulkhead  212  compresses the bond line and causes the adhesive to spread, which may squeeze out some of the uncured adhesive. As such, the cavity may additionally include a channel formed in the base to accommodate excessive squeeze out of the adhesive and therefore avoid interference of the adhesive with conductors on the bulkhead. 
     When positioned in the cavity  204 , the bulkhead  212  sits atop the pads  206  protruding from the bottom surface  208  such that the configuration creates a space between the bulkhead  212  and the bottom surface  208  of the cavity  204 . This space is arranged to contain the adhesive, which couples the bulkhead  212  to the bottom surface  208  of the cavity  204  and creates a seal that mitigates gas leakage from an interior portion of the hard disk drive. Dimensions of the adhesive are controlled by the size, shape, depth of the pads  206 . For example, the height of the pads (or alternatively, the depth of the pocket defined by protrusions) defines a thickness of the adhesive. The dimension for the height of the pads is shown by reference number  218 . The width of the adhesive is shown by reference number  220 . The wider and thinner the adhesive, the more restrictive the adhesive is to leakage (e.g., transmission of low density gas through the adhesive). However, if the adhesive is too thin, then structural integrity of the joint becomes a problem. For example, the weaker the adhesive is, the more susceptible the joint is to cracking at the due to thermal mismatch of the materials. Moreover, if the adhesive is too thin, during squeeze out, the adhesive may not flow properly which can cause voids in the cured adhesive. In some configurations, Applicants have found adhesives with a height of 0.002 inches and width of 0.110 inches provides both sufficient leakage mitigation and structural integrity for joining and maintaining a joint of a bulkhead to a hard disk drive base. 
       FIGS. 4 and 5  provide views of cavities in a hard disk drive base, in accordance with certain embodiments of the present disclosure. These figures show that pads positioned in the cavity can be shaped and positioned a variety of configurations.  FIG. 4  shows a cavity  400  with four pads  402  positioned in corners of the cavity and curved. The pads  402  can be created by machining and therefore may be integral to and made of the same material as the base of a hard disk drive. Alternatively, the pads may be a separate part and need to be positioned and joined to the base of a hard disk drive.  FIG. 5  shows a top view of a cavity  500  with a bulkhead  502  positioned in the cavity  500 . The bulkhead  502  rests on pads  504  positioned in the bottom of the cavity  500 . The bulkhead  502  has various electrical conductors  506 , which facilitate transmission of electrical signals through the bulkhead  502  and thus to and from a hard disk drive. 
       FIGS. 6 and 7  provide views of cavities  600 ,  700  in a hard disk drive base. The cavities  600 ,  700  have steps or protrusions  602 ,  702  in different configurations. In  FIG. 6 , the cavity  600  has two steps  602  (one not shown) on opposite ends of the cavity  600 . In  FIG. 7 , the cavity  700  has a single step  702  that wraps around the entire cavity  700 . 
       FIG. 8  shows a hard disk drive base  800 , a conductive bulkhead  802 , electrical connector  804 , and a printed circuit board (PCB)  606 , in accordance with certain embodiments of the present disclosure. The bulkhead  802  is positioned in a cavity of the base  800  and outside an internal housing of the hard disk drive. The electrical connector  804  is positioned inside the hard disk drive. The PCB  806  is mechanically coupled to the base  800  and is positioned outside the hard disk drive. The bulkhead  802  is mechanically coupled to the base  800  by an adhesive  808 . The bulkhead  802  and electrical connector  804  and PCB  806  are electrically coupled by electrical contacts  810  to a bulkhead&#39;s conductors—thus facilitating transmission of electrical signals to and from the hard disk drive. 
       FIG. 9  shows a hard disk drive base  900  and bulkhead  902 . The base  900  has a bottom surface  904  with a cavity  906 . In this embodiment, the bulkhead  902  is not positioned within the cavity  906 . Instead, the bulkhead  902  is configured to have its corners rest on the bottom surface  904  such that the bulkhead covers the cavity  906 . The bulkhead  902  is attached to the base  900  by an adhesive. Dimensions of the adhesive are controlled by the size, shape, depth of the cavity  906 . 
       FIG. 10  shows a hard disk drive base  1000  and bulkhead  1002 . The base  1000  has a bottom surface  1004  with a through hole  1006  and four protrusions  1008  positioned around the through hole  1006 . The bulkhead  1002  is configured to have its corners rest on the protrusions  1008  such that the bulkhead covers the through hole  1006 . The bulkhead  1002  is attached to the base  1000  by an adhesive. Dimensions of the adhesive are controlled by the size, shape, depth of the protrusions  1008  as described above. 
       FIGS. 9 and 10  show that the bulkhead is positioned external to the hard disc drive, but the disclosure is not so limited. Applicants recognize that bulkheads can be positioned in the interior surface along with other hard disc drive components. 
     It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangements of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.