DATA STORAGE DEVICES WITH AIR MOVERS

An electronic device includes an enclosure, an air mover assembly, and a printed circuit board. The enclosure houses electrical components. The air mover assembly includes at least a portion of a motor, and the printed circuit board is spaced from the enclosure and includes stator coils of the motor within the printed circuit board.

SUMMARY

In certain embodiments, an electronic device includes an enclosure that houses electrical components, an air mover assembly with at least a portion of a motor, and a printed circuit board spaced from the enclosure and including stator coils of the motor within the printed circuit board.

In certain embodiments, the air mover assembly includes a motor with a stator and a rotor. The stator includes stator coils, and the rotor includes a base that is coupled to a permanent magnet that has blades extending from the base. The air mover assembly further includes a printed circuit board with the stator coils positioned within the printed circuit board.

In certain embodiments, a method includes selectively energizing a set of stator coils to generate magnetic fields, where: the stator coils extend within a common plane, the stator coils are embedded in a printed circuit board, and the generated magnetic fields are directed along a direction perpendicular to the common plane. The method further includes rotating a rotor around the direction perpendicular to the common plane, where: the rotor includes a permanent magnet positioned on a first side of the rotor facing the printed circuit board and the rotor includes blades.

DETAILED DESCRIPTION

Data storage systems are used to store and process vast amounts of data. It can be challenging to keep the systems and their components (e.g., data storage devices) within a desired temperature range because of the amount of heat the systems and their components typically generate during operation. Certain embodiments of the present disclosure are accordingly directed to approaches for cooling data storage devices. In particular, certain embodiments involve incorporating air mover assemblies with data storage devices.

FIG.1shows an exploded, perspective view of a data storage device such as a hard disk drive100. Although a hard disk drive is used as an example throughout the description, the various features for cooling the hard disk drive100can be used in connection with other electronic devices and data storage devices.

The hard disk drive100includes a base deck102(which can also be referred to as a baseplate) and a top cover104that, when coupled together, creates an enclosure that houses various components of the hard disk drive100. The hard disk drive100includes magnetic recording media106(individually referred to as a magnetic recording medium) coupled to a spindle motor108by a disk clamp110. The hard disk drive100also includes an actuator assembly112that positions read/write heads114over data tracks116on the magnetic recording media106.

During operation, the spindle motor108rotates the magnetic recording media106while the actuator assembly112is driven by a voice coil motor assembly118to pivot around a pivot bearing120. The read/write heads114write data to the magnetic recording media106by generating and emitting a magnetic field towards the magnetic recording media106which induces magnetically polarized transitions on the desired data track116. The magnetically polarized transitions are representative of the data. The read/write heads114sense (or “read”) the magnetically polarized transitions with a magnetic transducer. As the magnetic recording media106rotate adjacent the read/write heads114, the magnetically polarized transitions induce a varying magnetic field into a magnetic transducer of the read/write heads114. The magnetic transducer converts the varying magnetic field into a read signal that is delivered to a preamplifier and then to a read channel for processing. The read channel converts the read signal into a digital signal that is processed and then provided to a host system (e.g., server, laptop computer, desktop computer).

FIG.2shows a cut away schematic of the hard disk drive100. The base deck102includes side walls (e.g., side wall122) that, together with a bottom portion124of the base deck102and a process cover126, creates an internal cavity128of an enclosure that houses various data storage components. During assembly, the process cover126can be coupled to the base deck102by removable fasteners (not shown) and a gasket (not shown) to seal a target gas (e.g., air with nitrogen and oxygen and/or a lower-density gas like helium) within the internal cavity128. Once the process cover126is coupled to the base deck102, a target gas may be injected into the internal cavity128through an aperture in the process cover126, which is subsequently sealed. Injecting the target gas, such as a combination of air and a low-density gas like helium (e.g., 90 percent or greater helium), may involve first evacuating existing gas from the internal cavity128using a vacuum and then injecting the target gas from a low-density gas supply reservoir into the internal cavity128. Once the process cover126is sealed, the hard disk drive100can be subjected to a variety of processes and tests. After the hard disk drive100is processed and passes certain tests, the top cover104can be coupled (e.g., welded) to the base deck102.

FIG.2shows the hard disk drive100including a printed circuit board130coupled to the base deck102(e.g., to the bottom portion124of the base deck102). The printed circuit board130can be coupled via fasteners that extend through openings in the board and into the base deck102.

The printed circuit board130includes one or more integrated circuits132. As shown inFIG.2, the integrated circuits132are positioned on a top surface134of the printed circuit board130that faces a bottom surface136of the base deck102. The integrated circuits132extend within a space138between the base deck102and the printed circuit board130. In certain embodiments, the distance between the top surface134of the printed circuit board130and the bottom surface136of the base deck102is 2-3 millimeters.

During factory testing and in-the-field operation of the hard disk drive100, the integrated circuits132are powered on to carry out various operations of the hard disk drive100. For example, the integrated circuits132can include a system-on-a-chip (SOC) that includes firmware and various microprocessors that manage operations of the hard disk drive100. These integrated circuits132generate heat when operating.

FIG.3shows a bottom view of the hard disk drive100with the printed circuit board130attached to the base deck102.FIG.4shows a bottom view of the hard disk drive100with the printed circuit board130detached to show example positions of the integrated circuits132coupled to the printed circuit board130. When the hard disk drive100is operating, these integrated circuits132generate heat in the space (e.g., the space138shown inFIG.2) between the printed circuit board130and the base deck102. The generated heat can create areas of concentrated heat (e.g., local hot spots), which can negatively affect performance of the integrated circuits132and the hard disk drive100. It can be challenging to cool this space and mitigate the risk of hot spots.

To help cool the space (e.g., the space138shown inFIG.2), the hard disk drive100can include an air mover assembly140, which is shown inFIG.4. Although only one air mover assembly140is shown, the hard disk drive100can include multiple air mover assemblies.

The air mover assembly140can be positioned within the space between the base deck102and the printed circuit board130and can be coupled to the printed circuit board130. As will be described in more detail below, the air mover assembly140can include fan blades150that are rotated to help increase air flow within the space and reduce the risk or extent of local hot spots. The air mover assembly140can be positioned, for example, between integrated circuits126to help induce airflow across the integrated circuits126. In other embodiments, the air mover assembly140is positioned at, or adjacent to, known hot spot locations.

FIG.5shows a schematic, cutaway side view of the air mover assembly140and a portion of the printed circuit board130and base deck102of the hard disk drive100.

The air mover assembly140is rotated by a motor, which comprises a rotor portion142(hereinafter “the rotor142” for brevity) and a stator portion144(hereinafter “the stator144” for brevity). Together, the rotor142and the stator144form the motor.

The rotor142is part of the air mover assembly140and includes a base portion146(hereinafter the “base146” for brevity). In certain embodiments, the base portion146is a toroidal-, disk-, frustoconical-, or plate-shaped structure although other shaped structures could be used. The rotor142can also include multiple permanent magnets148coupled to the base146. The rotor142can also include fan blades150(described in more detail below) that are integrally formed with the base146or separately coupled to the base146.

The base146is coupled to a bearing152, which allows the base146to rotate with respect to a shaft154(e.g., stationary shaft) that is coupled between the bearing152and the printed circuit board130. The bearing152can include grease, lubricant, ball bearings, etc., to permit the base146to rotate with a low amount of friction between the stationary and rotating parts of the bearing152.

The stator144includes stator coils156(e.g., conductive windings) that are positioned within the printed circuit board130. For example, the stator coils156can be embedded within the printed circuit board130. By positioning the stator coils156within the printed circuit board130(as opposed to being positioned external to the printed circuit board130), the overall height of the motor can be reduced. As a result, the hard disk drive100can include the air mover assembly140without necessarily needing to increase the space between the printed circuit board130and base deck102while still being able to fit within standard hard disk drive form factors. The hard disk drive100can therefore fit into standard-sized storage slots in server enclosures, desktops, etc.

The printed circuit board130can include traces158(e.g., conductive traces) that are electrically coupled to the stator coils156to provide power to (and therefore energize) the stator coils156. The traces158can be electrically coupled between the stator coils156and a power source, such as one of the integrated circuits on the printed circuit board130(e.g., the integrated circuits132shown inFIGS.2and4).

The stator coils156can be created as part of the process of creating the printed circuit board130. For example, the stator coils156can be made of a conductive material like the traces158. In printed circuit boards, conductive elements can be protected from electric shorts by being covered by an insulating material like a resin, which is sometimes referred to as a solder mask or solder resist. As such, the stator coils156and the traces158can both be embedded within a cured resin of the printed circuit board130.

When the stator coils156are energized, the stator coils156create magnetic fields that interact with the magnetic fields created by the permanent magnets148of the rotor142. The stator coils156can be selectively energized to cause the rotor142(and therefore the fan blades150) to rotate around a rotation axis160. The stator coils156can be designed and oriented to generate magnetic fields in an axial direction (e.g., a direction parallel to the rotation axis160). As such, in certain embodiments, the rotor142and the stator144can form an axial flux motor. Moreover, the rotor142and the stator144can form a brushless direct current (BLDC) motor such as a 3-phase BLDC motor.

In certain embodiments, the stator coils156are selectively energized such that the rotor142rotates at one or more speeds within the range of 500-1,500 revolutions per minute (rpm). At 1,000 rpm, the stator coils156may consume a relatively low amount of power such as 80-100 milliwatts. In certain embodiments, the particular rotating speed—or whether any power is provided to the stator coils156—can depend on factors such as temperature measurements (e.g., from the hard disk drive's temperature sensor) and/or power consumption of other components of the hard disk drive100. As such, the power consumption of the motor can be modified depending on the current operating environment of the hard disk drive100.

Although the fan assembly140will generate vibration during operation, little vibration is ultimately transferred to the base deck102of the hard disk drive100because the motor is held by the printed circuit board130. The mass of the printed circuit board130helps isolate and dampen the vibration created by the air mover assembly140. In certain embodiments, the printed circuit board130is a rigid printed circuit rather than a flexible printed circuit.

FIGS.6A and6Bshow different arrangements of the rotor142. The Figures show a bottom surface of the rotor142which is the surface facing the top surface of the printed circuit board. InFIG.6A, the rotor142includes four separate permanent magnets148. These permanent magnets148can be attached (e.g., adhered) to the disk146of the rotor142. The permanent magnets148can have different polarities and be arranged such that, for example, a negative polarity permanent magnet148is positioned between two positive polarity permanent magnets148. The number of permanent magnets148and the number of magnetic poles can vary depending on factors such as the size of the base146, size of the permanent magnets148, and desired performance of the motor.

InFIG.6B, the rotor142includes a single permanent magnet148. The permanent magnet148can be attached (e.g., adhered) to the base146of the rotor142. The permanent magnet148can be magnetized to have different magnetic poles along the radial direction of the permanent magnet148such that the single permanent magnet148functions the same as having several separate permanent magnets with different polarities. Using a single permanent magnet can simplify construction of the air mover assembly140.

FIG.7shows a top view of a portion of the printed circuit board130with the stator coils156exposed. As previously noted, the printed circuit board130houses the stator coils156. The stator coils156can include different sets of windings.

In certain embodiments, like that shown inFIG.7, the stator coils156include six separate sets of coils although the stator coils156may include fewer or more sets of coils. Each separate set of coils can include a specified number of windings. In embodiments, the number of windings of each set of coils is 5-8. The shape of the sets of coils can vary but are typically triangular-shaped—although the tips of the triangles can be more rounded than that shown inFIG.8. The stator coils156can be planar such that all the coils are positioned along the same common plane within the printed circuit board130. This shared common plane can be parallel to the top surface of the printed circuit board130. In certain embodiments, the stator144is considered to be a coreless stator because the stator coils156are not wound around a magnetic core.

As noted above, the stator coils156can be electrically coupled to traces, which provide power to the stator coils156. Each of the separate sets of coils can be coupled to a trace of the printed circuit board130and wired such that the stator144creates a 3-phase motor. When the stator coils156are energized, the stator coils156create magnetic fields that are directed towards a direction out of the page ofFIG.7(e.g., perpendicular to the shared common plane the stator coils156are positioned within or perpendicular to the top surface of the printed circuit board130). The different sets of coils can be selectively energized over time to create magnetic fields that interact with those of the permanent magnets to cause the rotor142to rotate.

FIG.8shows another example of a printed circuit board200with an air mover assembly202. The printed circuit board200can be coupled to an electronic device such as the hard disk drive100described above.

The air mover assembly202includes a rotor204with a cylinder-shaped base portion206. The air mover assembly202also includes blades208. In certain embodiments, the base206and the blades208are a unitary structure. For example, the base206and the blades208can be formed by a single mold.

FIG.9shows a closer-up view of the rotor204. As shown, the base206includes a central opening210, which can be sized to allow a shaft to extend through. The blades208extend from the base206perpendicular to a rotation axis212around which the rotor204rotates. In the embodiment shown inFIG.9, the rotor204includes three blades208, however, the rotor204could include additional blades.

FIG.10shows a top view of the rotor204. As can be seen inFIG.10, as the blades208extend from the base206to a distal end214, a thickness (T) of the blades208decreases such that the thickness is the greatest at the base206and smallest at the distal end214. In certain embodiments, the blades208have identical geometry and are positioned 120 degrees from each other along the base206.

Each blade208has a leading surface216that pushes air as the rotor204rotates around the rotation axis212. The leading surface216can be curved such that a bottom leading edge218of the blades208is offset from a top leading edge220of the blades208. As such, the leading surface216is slanted so that air is pushed away from the printed circuit board as the rotor204rotates.

Using the air mover assemblies described above, the rotating blades of the air mover assemblies cause air to move within the space between the printed circuit board and the base deck. As the air moves across and around the integrated circuits, heat generated by the integrated circuits can be circulated to other locations within the space or outside the space entirely to help reduce the risk of local hot spots.

FIG.11shows a block diagram of a method300. The method300includes selectively energizing a set of stator coils to generate magnetic fields directed along a direction perpendicular to a common plane of the stator coils (block302inFIG.11). The method300further includes rotating a rotor around the direction perpendicular to the common plane (block304inFIG.11). The method300may also include the various steps or processes described above and utilize the various devices, assemblies, and components described above.

Various modifications and additions can be made to the embodiments disclosed without departing from the scope of this disclosure. For example, while the embodiments described above refer to particular features, the scope of this disclosure also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present disclosure is intended to include all such alternatives, modifications, and variations as falling within the scope of the claims, together with all equivalents thereof.