Integrated filter system for a data storage device

An apparatus for mitigating particle and aerosol contaminants from an internal environment of a data storage device is disclosed. The apparatus includes a base, a breather diffusion path formed in the base, a re-circulating filter channel adjacent the base, and an absorption filter chamber adjacent the re-circulating filter channel and communicating with the breather diffusion path.A breather filter removes particulates from air migrating through the diffusion path. The length and diameter of the diffusion path precludes transfer of humidity from the external environment of the data storage device to the internal environment of the data storage device. A re-circulating filter spans the re-circulating filter channel and removes particulates from airstreams passing through the re-circulating filter channel, and a substantially carbon based absorption filter extracts corrosive gases and organic vapors from the internal environment of the data storage device.

FIELD OF THE INVENTION

The claimed invention relates to the field of data storage devices. More particularly, but not by way of limitation, this invention relates to an all-in-one integrated filter system for minimization and control of internal contaminants of a data storage device.

BACKGROUND

One key component of a computer system is a data storage device, such as a disc drive. The most basic parts of a disc drive (drive) are a data storage disc (disc) that is rotated beneath a read/write head (head). Rotation of the disc beneath the head generates an air bearing upon which the head flies. An actuator moves the flying head to various locations over substantially concentric data tracks of the disc to facilitate data exchanges between the head and the disc, and electrical circuitry encodes the data being exchanged and controls drive operations including control of the exchange of data between the computer system and the disc.

Airborne contaminants including particulates, corrosive gases and organic vapors pose reliability issues for the drive. Particulates can disrupt the air bearing causing the head to lose flight and impact the disc. Physical contact between the head and disc during drive operations expose the head and disc to damage, either a catastrophic failure (i.e., a head crash) or surface wear, which degrades drive reliability. Corrosive gases and organic vapors that interact with surface materials of the disc and head causing stiction between the head and disc, or promoting growth of asperities on the disc, further impair drive reliability.

Sources of corrosive gases and organic vapors may be found in the environment external to the drive, for example in a situation where the drive supports a control processor controlling chemical processing operations, or they may originate from materials used in the construction of the drive, such as gaskets, seals or adhesives. An out-gassing over time of volatiles from seals, gaskets or adhesives is typically a relatively slow process; however the aggregate accumulation of the out-gassing material may cause stiction between the head and disc, or promoting growth of asperities on the disc.

As such, challenges remain and a need persists for improvements in filter systems to cost effectively mitigate contaminants impacting operations of data storage devices.

SUMMARY OF THE INVENTION

In accordance with preferred embodiments, an apparatus and combination are provided for mitigating contaminants from an interior environment of a data storage device. The combination includes a base deck with a disc stack assembly attached to the base deck and an actuator assembly adjacent the disc stack assembly secured to the base deck. The disc stack assembly includes a motor assembly that supports and rotates a data storage disc. A read/write head is supported by the actuator assembly, which rotates a read/write head adjacent the disc in a data exchange relationship with the disc.

Also included in the combination is a top cover attached to the base deck, which encloses the disc stack assembly and the actuator assembly within a confined environment, and a filtering apparatus for filtering contaminants from the confined environment.

The filtering apparatus filters contaminants from the confined environment of the data storage device and includes a base, a breather diffusion path formed in the base, a re-circulating filter channel adjacent the base and an absorption filter chamber adjacent the re-circulating filter channel. The absorption filter communicates with the breather diffusion path via a diffusion aperture. A re-circulating filter is confined within the re-circulating filter channel by a pair of re-circulating filter grooves, the absorption filter chamber houses a carbon based absorption filter and a breather filter communicates with the breather diffusion path to filter particulate contaminants from an environment external to the data storage device.

The carbon based absorption filter absorbs corrosive gases and organic vapors from the confined environment of the data storage device. The filtering apparatus also includes a surface filter medium partially lining the re-circulating filter channel, and a shroud filter wall adjacent the absorption filter chamber, which supports an impact filter medium. The surface filter medium assists in removal of particle and aerosol contaminants from the confined environment of the data storage device and the impact filter medium removes particles from air flow, (generated by rotation of the disc) that avoids passage through the re-circulating filter channel.

These and various other features and advantages that characterize the claimed invention will be apparent upon reading the following detailed description and reviewing the associated drawings.

DETAILED DESCRIPTION

Referring now to the drawings,FIG. 1provides a top plan view of a data storage device (DSD)100. The DSD100includes a base deck102cooperating with a top cover104(shown in partial cutaway) to form a sealed housing (also referred to as a confined environment) for a mechanical portion of the DSD100, referred to herein as a head-disc assembly106.

A spindle motor assembly108(also referred to as motor108) rotates a number of data storage discs (discs)110at a substantially constant operational speed. Each disc110includes at least one magnetic recording surface112. The spindle motor assembly108with the disc110attached thereon form a disc stack assembly114. An actuator assembly116supports a number of read/write heads (heads)118. The heads118are used for data exchange operations with the magnetic recording surface112. Upon applying a current to a coil120of a voice coil motor (VCM)122, the actuator assembly116, which is attached to the coil120, responds by rotating the heads118to a position adjacent the magnetic recording surfaces112.

During operation of the DSD100, the actuator116rotates the heads118into a data exchange relationship with data tracks124on the magnetic recording surface112to write data to and read data from the discs110. When the DSD100is deactivated, the actuator116positions the heads118adjacent a home position126and the actuator116is confined by latching a toggle latch128.

Command, control and interface electronics for the DSD100are provided on a printed circuit board assembly130mounted to the head-disc assembly106. During data transfer operations, a preamplifier/driver (preamp)132attached to a flex circuit134conditions read/write signals conducted by the flex circuit134between the printed circuit board assembly130and the heads118.

During operation of the DSD100, a filter apparatus136located in the base deck102and adjacent the disc stack114, mitigates particulate and aerosol contaminants from within the confined environment of the head-disc assembly106. Included in the filter apparatus136, is a re-circulating filter138. A breather aperture140, shown through a partial cut-away of the filter apparatus136, is provided in the base deck102to exchange air between the environment external to the head-disc assembly106to the confined environment within the head-disc assembly106.

FIG. 2shows a first re-circulating filter channel wall142with a first re-circulating filter retention groove144, and a second re-circulating filter channel wall146with a second re-circulating filter retention groove148. In a preferred embodiment, the structure of the filter apparatus136, as illustrated byFIG. 2, is formed from a molded polymer. However, non-magnetic ridged metals or ceramics may be elected to form the filter apparatus136. The material elected may be cast or machined, or cast and machined.

The first and second re-circulating filter retention grooves,144and148, retain the re-circulating filter138during operations of the DSD100, while a base150supports the re-circulating filter138from below. In other words the base150communicates with the first re-circulating filter channel wall142(which includes the first re-circulating filter retention groove144) and the second re-circulating filter channel wall146(which includes the second re-circulating filter retention groove148) to form the confines for retaining the re-circulating filter138within the filter apparatus136.

Additionally,FIG. 2shows a cover152supported by the second re-circulating filter channel wall146(the internal surface of the second re-circulating filter channel wall146is illustrated by a hidden line).

FIG. 3shows a breather diffusion path154formed in the base150. In a preferred embodiment of the DSD100, the breather diffusion path154communicates with a diffusion aperture156at a proximal end of the breather diffusion path154and the breather aperture140(ofFIG. 1) at a distal end of the breather diffusion path154. Collectively, the breather aperture140, the breather diffusion path154and the diffusion aperture156permit passage between the environment external to the head-disc assembly106(ofFIG. 1) and the environment confined within the head-disc assembly106.

The breather aperture140and the diffusion aperture156facilitate equalization of interior and exterior atmospheric pressures of the head-disc assembly106(ofFIG. 1). Equalization of interior and exterior atmospheric pressures minimizes a risk of damage to seals and gaskets of the head-disc assembly106, in particular, seals used by the motor108(ofFIG. 1).

The breather diffusion path154has a predetermined cross-sectional area and a predetermined overall length that permits passage between the internal and external environments of the head-disc assembly106while precluding passage of humidity between the two environments.

As will be discussed in greater detail below, a breather filter (not shown) is interposed across the passage between the environment external to the head-disc assembly106and the environment confined within the head-disc assembly106. The breather filter may be positioned in any convenient location along the passage to primarily prevent ingress of particulate contaminants from the external environment.

FIG. 4shows a re-circulating filter channel158adjacent the base150, and an absorption filter chamber160adjacent the base150and adjacent the second re-circulating filter retention groove148. The base150communicates with the first re-circulating filter channel wall142and the second re-circulating filter channel wall146to form boundaries of the re-circulating filter channel158.

Also shown byFIG. 4is a shroud filter wall162, a first absorption filter confinement wall164and a second absorption filter confinement wall166. The shroud filter wall162in conjunction with the first and second absorption filter confinement walls,164and166, provide additional support for the cover152(ofFIG. 2).

FIG. 4further shows an absorption filter aperture168provided by the second absorption filter confinement wall166. The absorption filter aperture168promotes access for placement of an absorption filter (not shown) within the absorption filter chamber160.

FIG. 5shows a breather filter170adjacent the breather aperture140and supported by the base deck102. The breather filter170filters particle and aerosol contaminants from an air stream migrating through the breather diffusion path154(ofFIG. 3).

FIG. 6shows a surface filter medium172partially lining the inner walls of the re-circulating filter channel158, and an impact filter medium174supported by an external surface of the shroud filter wall162. It has been found that a hepa type filter with electrostatic media is a useful medium for both the impact filter medium174and the surface filter medium172. As the disc110(ofFIG. 1) rotates, air flows from the inner diameter to the outer diameter of the disc110. A portion of the air flow generated by rotation of the disc110enters the re-circulating filter channel158and continues until the air flow impacts the re-circulating filter138. Particles supported by the air flow are removed from the air flow by the re-circulating filter138.

However, upon impacting the re-circulating filter138, air flowing through the re-circulating filter channel158is retarded. Flow retardation produces vortices and back-flow. By partially lining the re-circulating filter channel158with the surface filter medium172, contaminants caught up in the turbulence created by the re-circulating filter138will interact with the surface filter medium172and be removed from the air flow.

Similarly, air flow developed by rotation of the disc110that fails to enter the re-circulating filter channel158impacts the shroud filter wall162, and particles carried along by the air flow are collected by the impact filter medium174.

In an alternate embodiment shown byFIG. 7, the breather filter170is adjacent the diffusion aperture156and supported by the base150of the filter apparatus136. During operation of the DSD100(ofFIG. 1), the breather filter170filters particle and aerosol contaminants from air exchange between the confined environment within the head-disc assembly106(ofFIG. 1) and the environment external to the head-disc assembly106.

FIG. 8shows the top view of the relationship between the impact filter medium174and the surface filter medium172, as well as the direction of air flow of an air stream176as the air stream176progresses through the re-circulating filter138of the filter apparatus136.

FIG. 9shows an absorption filter178positioned within the absorption filter chamber160. Corrosive gases and organic vapors carried along in the air stream176(ofFIG. 8) that fail to be collected by the re-circulating filter138are collected by the absorption filter178. Although other materials may be used, granular carbon structures with a large surface area, as well as carbonate coated carbon structures have been found useful in forming the absorption filter178.

FIG. 10shows an alternate preferred embodiment of the filter apparatus136presenting the top view of the relationship between the impact filter medium174and the surface filter medium172, as well as the direction of air flow of an air stream176as the air stream176progresses through the re-circulating filter138of the filter apparatus136along with an alternate configuration and mounting location for the breather filter170.

FIG. 11shows an absorption filter178positioned within the absorption filter chamber160. Corrosive gases and organic vapors carried along in the air stream176(ofFIG. 8) that fail to be collected by the re-circulating filter138are collected by the absorption filter178.FIG. 11additionally shows a partial cutaway view of the breather filter170mounted adjacent the absorption filter178.

An airflow passing through the diffusion aperture156(ofFIG. 10) from the external environment to the internal environment of the head-disc assembly106(ofFIG. 1) first encounters the absorption filter178, which absorbs corrosive gases and organic vapors present in the airflow. Particulates present in the airflow, not bound up in the absorption filter178, are extracted from the airflow by the breather filter170.

It is noted that, although the breather filter170is not in direct communication with the diffusion aperture156, the breather filter170remains a breather filter. As shown byFIG. 11, the breather filter170is conveniently interposed across the airflow between the environment external to the head-disc assembly106and the environment confined within the head-disc assembly106(i.e., the airflow passing through the diffusion aperture156(ofFIG. 10) from the external environment to the internal environment of the head-disc assembly106and subsequently through the absorption filter178,) to primarily prevent ingress of particulate contaminants from the external environment from contaminating the internal environment of the head-disc assembly106.

Accordingly, embodiments of the present invention are generally directed to a filter apparatus (such as136) and a combination that includes a base deck (such as102) supporting a disc stack assembly (such as114) with a disc (such as110) attached thereon, and an actuator assembly (such as116) supporting a read/write head (such as118). Additionally, the combination includes a top cover (such as104) attached to the base deck that encloses the disc stack assembly and the actuator assembly within a confined environment of the combination along with the filter apparatus.

The filtering apparatus filters contaminants from the confined environment of the combination. The filtering apparatus includes a base (such as150) with a breather diffusion path (such as154) formed in the base, a re-circulating filter channel (such as158) adjacent the base, and an absorption filter chamber (such as160) communicating with the breather diffusion path and located adjacent the re-circulating filter channel.

A re-circulating filter (such as138) is confined within the re-circulating filter channel by a pair of re-circulating filter retention grooves (such as144and148). The absorption filter chamber houses a carbon based absorption filter (such as178), and a breather filter (such as170) communicates with the breather diffusion path to filter particulate contaminants from entry into the confined environment of the combination. The carbon based absorption filter absorbs corrosive gases and organic vapors from the confined environment of the combination.

The filtering apparatus also preferably includes a surface filter medium (such as172) partially lining the re-circulating filter channel, and a shroud filter wall (such as162) adjacent the absorption filter chamber supporting an impact filter medium (such as174). The surface filter medium assists in removal of particle and aerosol contaminants from the confined environment of the combination and the impact filter medium removes particles from air flow that avoids passage through the re-circulating filter channel.

It will be clear that the present invention is well adapted to attain the ends and advantages mentioned as well as those inherent therein. While presently preferred embodiments have been described for purposes of this disclosure, numerous changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the appended claims.