Acoustic damping pad that reduces deflection of a circuit board

A acoustic damping pad is provided. The acoustic damping pad includes a first surface and an opposing second surface that are defined by a periphery. A first set of perforations extend between the first surface and the second surface of the acoustic damping pad. Each adjacent perforation in the first set of perforations is uniformly spaced apart from each other across a first select surface area of the first surface and across a corresponding first select surface area of the opposing second surface to form a uniform pattern.

BACKGROUND

A data storage system, such as a disc drive, includes a base and a top cover that houses a variety of internal components. Example internal components include one or more data storage discs, a spindle motor and a spindle hub. The disc(s) are mounted to the spindle hub and the spindle motor drives the spindle hub which rotates the disc(s). A disc drive also includes external components. An example external component includes a printed circuit board assembly (PCBA). The PCBA is attached to an outer surface of the base.

Acoustic noise can be generated from the rotation of the spindle motor and the attached disc(s). Acoustic noise can also be generated from the actuator assembly that supports read/write heads which read and write data to the storage disc(s). A base and top cover house internal components of the disc drive and can amplify the sources of acoustic noise discussed above. More specifically, the base and top cover can substantially add to acoustic noise due to their resonance characteristics.

Independent of acoustic noise, mechanical resonance associated with components of the disk drive, such as operation of the actuator assembly, can result in read/write errors due to track misregistration. Disc drives with high track densities are particularly prone to track misregistration errors that can arise from excessive mechanical resonances. To alleviate vibration and acoustic noise as well as to provide dampening of mechanical resonances, a layer of damping material can be secured to the outer surface of the base between the PCBA, and the base.

The PCBA is used to compress the damping material against the base so that the damping material can perform its acoustic damping functions. Typically, screws are used to secure the PCBA to the base. The compression of the damping material forms a constrained layer that dissipates acoustic energy and mechanical vibration emitted by the disc drive. Additionally, the damping material acts to electrically insulate the PCBA from the drive housing.

When the PCBA is secured to the base, the pressure that the damping material applies to the PCBA in response to the compression again the base causes the PCBA to deflect outwardly away from the drive housing. With a sufficient amount of deflection, the disc drive can no longer comply with established dimensional form factor. In some instances, the deflection of the PCBA can be great enough that when the disc drive is installed in the designated computing device, damage to the disc drive occurs by contact of the disc drive with the internal components of the computing device.

SUMMARY

An acoustic damping pad is provided to alleviate vibration and acoustic noise. The acoustic damping pad includes a first surface and an opposing second surface that are defined by a periphery. A first set of perforations extend between the first surface and the second surface of the acoustic damping pad. Each adjacent perforation in the first set of perforations is uniformly spaced apart from each other across a first select surface area of the first surface and across a corresponding first select surface area of the opposing second surface to form a uniform pattern.

These and various other features and advantages will be apparent from a reading of the following Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.

DETAILED DESCRIPTION

FIG. 1illustrates a simplified schematic diagram of a data storage system100in which one or more embodiments of the present disclosure are useful. In one embodiment, data storage system100includes a disc drive. One or more embodiments of the present disclosure are also useful in other types of data storage and non-data storage systems.

Data storage system100includes an enclosure101that encloses a plurality of components such as a disc medium107. Those skilled in the art should recognize that disc drive100can contain a single disc, as illustrated inFIG. 1, or multiple discs. As illustrated inFIG. 1, disc107is mounted on a spindle motor105for rotation about central axis109. Each disc surface has an associated slider110. Each slider110carries a read/write head for communication with the surface on the disc. Each slider110is supported by a suspension112which is in turn attached to a track accessing arm114of an actuator mechanism116. Actuator mechanism116is rotated about a shaft by a voice coil134of a voice coil motor118. As voice coil motor118rotates actuator mechanism116, slider110moves in an arcuate path122between a disc inner diameter124and a disc outer diameter126.

FIG. 2illustrates data storage system100including one embodiment of an acoustic damping pad10compressed between a base12, and a printed circuit board assembly (PCBA)14. Base12forms a portion of the enclosure101(FIG. 1) of data storage system100. Acoustic damping pad10is secured to base12, and PCBA14is mounted over pad10to base12. Although not illustrated inFIG. 2, in some embodiments, acoustic damping pad10is compressed between a top cover (not illustrated) and PCBA14if PCBA14is configured for mounting to a top cover of a data storage system.

Base12can have a plurality of irregularities formed on an outer surface13thereof. InFIG. 2, base12can comprise a protrusion16to accommodate a spindle motor. A raised area18may also protrude from base12to accommodate internal components in data storage system100, such as the magnets and magnet plates that cooperate with the voice coil of the actuator (FIG. 1). Accordingly, surface13of base12is not simply planar, but has various irregularities formed thereon. In one embodiment when acoustic damping pad10is compressed between PCBA14and base12, raised areas on base12, such as raised area18and protrusion16, can apply pressure on acoustic damping pad10which can consequently deflect or put stress on PCBA14in regions that correspond with the raised areas.

Acoustic damping pad10includes a first surface19and an opposing second surface21and is defined by a periphery22. As shown, acoustic damping pad10is not simply rectangular shaped, and can have various features formed on periphery22to accommodate the corresponding irregularities formed on base12. Additionally, acoustic damping pad10can comprise one or more openings20that accommodate the irregularities in base12. For example, larger hole20may be provided to accommodate protrusion16.

PCBA14comprises a substrate30including a plurality of components formed thereon, such as various electronic components34. Substrate30may also comprise one or more openings32to accommodate the irregular features protruding from base12. Additionally, PCBA14includes a plurality of screw holes36which receive a plurality of screws (not shown) that compress first surface19of acoustic damping pad10against base12and also secures PCBA14to base12. In response to the screws that compress first surface19of acoustic damping pad10against base12, acoustic damping pad10can apply stress on PCBA14. Such stress can cause PCBA14to be deflected outwardly away from the data storage system enclosure. Deflection of PCBA14is undesirable especially in regions of the PCBA where the thickest components34are located on substrate30. Since PCBA14and acoustic damping pad10are usually only fastened to the base around their peripheries, PCBA14can also bow or deflect around the central area of the PCBA based on pressure derived from the compression on acoustic damping pad10by the plurality of screws.

With reference toFIGS. 2 and 3, acoustic damping pad10includes a perforation pattern24comprising a first set of perforations26that extend between first surface19and second surface21of acoustic damping pad10. Each adjacent perforation26is uniformly spaced apart from each other across a first select surface area25of first surface19and a corresponding first select surface area (hidden from view) of second surface21to form a uniform pattern24. InFIG. 3, the first set of perforations26are shown as having substantially similar sizes and shapes. It should be noted, however, that first set of perforations26can each include different sizes and shapes. For example, other geometric shapes besides circular shapes (as illustrated) can be used for first set of perforations26, such as ellipses, rectangles and etc. Different sizes and shapes allow acoustic damping pad10to capture different acoustic signatures.

In the embodiment illustrated inFIGS. 2 and 3, the first set of perforations26can be located on a select area of acoustic damping pad10which corresponds with areas of PCBA14that are under deflection. For example, first set of perforations26is located on a select area of acoustic damping pad10which abuts the raised area18on base12. As shown, first set of perforations26generally follows the shape of raised area18, and thus provides some additional flexibility for acoustic damping pad10at that location to prevent excess stress on PCBA14. Other areas of deflection on PCBA14can be determined by conducting a finite element analysis on PCBA14. Such an analysis can aid in selectively locating perforation pattern24on acoustic damping pad10in locations that correspond to locations on PCBA14which has the greatest amount of deflection.

FIG. 4illustrates another embodiment of an acoustic damping pad40. In this embodiment, acoustic damping pad40includes a periphery44having a first surface41and an opposing second surface43with the same general shape and configuration as acoustic damping pad10illustrated inFIGS. 2 and 3. Acoustic damping pad40also includes openings42that accommodate irregularities on the outer surface of a base. Acoustic damping pad40includes a perforation pattern46comprising a first set of uniformly spaced apart perforations48that is provided at a location different than the location of perforation pattern24on acoustic damping pad10illustrated inFIGS. 2 and 3. First set of perforations48extend between first surface41and second surface43. Each adjacent perforation48is uniformly spaced apart from each other across a first select surface area49of first surface41and a corresponding first select surface area (hidden from view) of second surface43to form uniform pattern24.

Although perforation pattern46includes a first set of perforations48that are circular in geometric shape like perforation pattern24of acoustic damping pad10, a distribution shape of perforation pattern46is different from a distribution shape of perforation pattern24on acoustic damping pad10. Perforation pattern46with first set of perforations48can be provided on acoustic damping pad40for a base having a different configuration of surface irregularities than that of base12illustrated inFIG. 1. For example, a finite stress element analysis might indicate that the most advantageous placement of perforations48are generally about the larger central opening42of which is provided to accommodate a large protrusion for a base having a large spindle motor. Therefore, inFIG. 4, the first set of perforations48is included in first select area49of first surface41, which is formed about the larger central opening42. In addition, first set of perforations48tend to be positioned at or near the central area of acoustic damping pad40which correspondingly abuts the central area of a PCBA, such as PCBA14. Such a central position helps eliminate the PCBA from deflecting outwardly due to compression of acoustic damping pad40by the plurality of screws. Again, other geometric shapes besides circular shapes (as illustrated) can be used for first set of perforations26, such as ellipses, rectangles and etc. Different sizes and shapes allow acoustic damping pad40to capture different acoustic signatures.

FIG. 5illustrates yet another embodiment of an acoustic damping pad50. In the embodiment illustrated inFIG. 5, acoustic damping pad50has a different periphery54than the acoustic damping pad peripheries22and44ofFIGS. 2-4. A periphery54of acoustic damping pad50defines a more rectangular shaped pad having a first surface51and an opposing second surface53. Pad50also has a pair of openings52to accommodate those corresponding irregularities on the surface of the base (not shown).

FIG. 5also illustrates acoustic damping pad50having two distinct and separate types of perforation patterns56and60. Perforation pattern56includes a first set of perforations58. The first set of perforations58provides a distributed pattern around the leftmost opening52, which accommodates irregularity on a base of a data storage system. First set of perforations58extend between first surface51and second surface53of acoustic damping pad50. Each adjacent perforation58is uniformly spaced apart from each other across a select first surface area59of first surface51and a corresponding first select surface area (hidden from view) of second surface53. Each perforation58in perforation pattern56includes a plurality of oval or elliptical-shaped perforations58to form uniform pattern56. Perforation pattern60includes a second set of perforations62. The second set of perforations62provide a distributed pattern around the rightmost opening52, which accommodates irregularity on a base of a data storage system. Second set of perforations62extend between first surface51and second surface53of acoustic damping pad50. Each adjacent perforation62is uniformly spaced apart from each other across a second select surface area63of first surface51and a corresponding second select surface (hidden from view) of second surface53. Each perforation62includes a plurality of circular-shaped perforations62to form uniform pattern60. However, it should be noted that perforation pattern56and60can include other shapes of perforations, besides circular and elliptical. For example, perforations can be rectangular in shape. In one embodiment and as illustrated inFIG. 5, second set of perforations62are smaller in size than the first set of perforations58. In addition, the second set of perforations62are generally spaced closer to one another than the first set of perforations58. Furthermore, in one embodiment, the distribution of perforation pattern62is different than that of the distribution of perforation pattern56.

Thus,FIG. 5illustrates that the perforation pattern(s) can comprise perforations arranged in different sets of distributions, shapes, sizes and spacing between the perforations. For example, a first set of perforations that form a perforation pattern can be provided for enabling an acoustic damping pad to more easily deflect or bend, while a second set of perforations that form a perforation pattern may be provided to tune the acoustic dampening performance to best match the resonant frequencies of acoustic noise produced by the data storage system. In addition, different sets of distributions, shapes, sizes and spacing between perforations can be optimized depending on the type of application. For example, perforations in an acoustic damping pad being utilized in a data storage system coupled to a small electronic device (such as a cell phone, PDA or digital music player) can be optimized due to the data storage system form factor versus an acoustic damping pad being utilized in a data storage system coupled to a desktop personal computer. Accordingly, the differently distributed, spaced and sized perforations between the perforation patterns are reflective of not only a finite element analysis of the PCBA, but also take into account an optimal perforation pattern to best tune the acoustic dampening performance of the insulating pad base on the application in which it is used.

There are a number of advantages in the above disclosed embodiments. A relatively simple yet effective modification can be made to a pad which remedies undesirable deflection in the PCBA. Form factor requirements may be met with the modified pad, without having to further modify other components of the disc drive. The particular selected perforation pattern can be chosen to provide the necessary amount of increased flexibility of the pad so that an undue amount of force is not transferred to the PCBA. Thus, the ability to specifically tailor the size, type, and number of perforations on the insulating pad provides a comprehensive solution for preventing undesirable PCBA deflection. Additionally, the perforations may be provided for purposes of tuning the acoustic dampening performance of the insulating pad to dampen the acoustic noises associated with operation of the disc drive.

It is to be understood that even though numerous characteristics and advantages of various embodiments of the disclosure have been set forth in the foregoing description, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. For example, the particular elements may vary depending on the particular application for the data storage system while maintaining substantially the same functionality without departing from the scope and spirit of the present invention. In addition, although the preferred embodiment described herein is directed to an acoustic damping and insulating pad for a disc drive, it will be appreciated by those skilled in the art that the teachings of the present invention can be applied to other types of data storage systems, without departing from the scope and spirit of the present invention.