Vibration isolating disk drive receiving stations and chassis used in the manufacture and/or testing of hard disk drives

A chassis for receiving a plurality of disk drives includes a plurality of disk drive receiving stations. Each station is configured to carry out testing and/or servo writing operations on a received disk drive. Each station includes a base, a nest assembly and a plurality of elastomeric mounts that elastically couple the nest assembly to the base to enable movement of the nest assembly relative to the base. The nest assembly includes a nest configured to receive and mate with the disk drive and a printed circuit board. Each station includes a separate vibration isolating mass that is coupled to the nest. The vibration isolating mass at least partially isolates vibrations originating within the nest from being transmitted through the elastomeric mounts to other nests in the chassis and at least partially isolates vibrations originating outside the nest from being transmitted through the elastomeric mounts to the nest assembly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to disk drives. More particularly, the present invention relates to vibration isolating disk drive receiving stations and chassis used in the manufacture and/or testing of disk drives.

2. Description of the Prior Art

FIG. 1shows the principal components of a magnetic disk drive100with which embodiments of the present invention may be practiced. The disk drive100comprises a head disk assembly (HDA)144and a printed circuit board assembly (PCBA)141. The elements shown and described inFIG. 1may be at least partially incorporated within the PCBA141. The HDA144includes a base161and a cover171attached to the base161that collectively house one or more disks200(only one disk102is shown inFIG. 1), a spindle motor113attached to the base161for rotating the disk102, a head stack assembly (HSA)150, and a pivot bearing cartridge184that rotatably supports the HSA150on the base161. The spindle motor113rotates the disk102at a constant angular velocity, subject to the above-described variations. The HSA150comprises a swing-type or rotary actuator assembly152, at least one head gimbal assembly that includes the suspension assembly154, a flex circuit cable assembly180and a flex bracket159. The rotary actuator assembly152includes a body portion145, at least one actuator arm cantilevered from the body portion145, and a coil assembly including a coil156cantilevered from the body portion145in an opposite direction from the actuator arm(s). A bobbin158may be attached to the inner periphery of the coil assembly to stiffen the coil assembly. The actuator arm(s) support respective suspension assembly(ies) that, in turn, support the head that includes the read/write transducer(s) for reading and writing to the disk102. The HSA150is pivotally secured to the base161via the pivot-bearing cartridge184so that the read/write transducer(s) at the distal end of the suspension assembly(ies) may be moved over the recording surface(s) of the disk(s)200. The pivot-bearing cartridge184enables the HSA150to pivot about its pivot axis. The “rotary” or “swing-type” actuator assembly rotates on the pivot bearing cartridge184between limited positions, and the coil assembly that extends from one side of the body portion145interacts with one or more permanent magnets190mounted to back irons170,172to form a voice coil motor (VCM). When a driving voltage is applied to the VCM, torque is developed that causes the HSA150to pivot about the actuator pivot axis and causes the read/write transducer(s) to sweep radially over the disk102.

Thereafter, the PCBA141may be mated to the HDA144and a variety of tests and procedures may be carried out to configure, validate and test the proper operation of the disk drive. Such testing may be carried out in a “single plug tester”, which is a test platform that includes a chassis that includes a bank of slots or bays into which the disk drives may be loaded and unloaded. A sequential series of tests and operations are then carried out on the loaded disk drives. Conventionally, the drives remain in the same bay during the administration of the entire sequence of configurations, validations and tests, and are removed at the conclusion of the sequence of operations and/or tests.

One of the first such operations may include loading necessary firmware and software into the drives. The next operations on the drive may include a seeded self-servo write procedure, in which servo information is written to the disk or disks of the drive. During this procedure, servo sector information is written to the drive without using a servo track writer. As servo track writing is a time consuming process that is directly proportional to the areal density of the disk, reducing the number of servo sectors the servo track writer lays down on the disk saves manufacturing time and costs.

Further operations may include a microcode download to the drive, which may be followed by an initial bum in self-test (IBI self-test), in which a lengthy calibration of the drive is performed, as well as procedures to discover, map and manage the defects on the media. The length of time necessary to complete this test is roughly proportional to the storage capacity of the drive under test.

The next and final operations may include administering final configurations and tests. During these operations, the drive communicates with a host computer, so as to verify the proper operation of host commands and to enable the host to analyze and validate the results of the IBI self-test. Other tests and procedures may be carried out on the drives under test, in addition or in place of the tests discussed above, such as a debug process when a fault is found during testing. Such debug tests may be performed to isolate faults, so as to facilitate the correction thereof.

Increasing aerial densities bring about a number of concerns that must be addressed during the administration of these operations and tests. For example, as the number of Tracks per Inch (TPI) of modern drives continues to increase, the drives become increasingly susceptible to vibrations during, for example, the seeded self servo write operations. Such vibrations may originate, for example, from outside of the chassis of the test platform on which these operations are carried out. While the chassis itself may be equipped with structures to mitigate the effects of such vibrations, such structures do not protect the individual drives loaded therein from vibrations that originate from within the chassis. Such vibrations may be generated from adjacent drives within the chassis, as they are subjected to the above-listed operations and tests.

From the foregoing, it may be appreciated that there is a need for vibration reducing structures that mitigate the effects of vibrations that could negatively affect the drive during these operations and test, whether such vibrations originate from within or outside of the chassis in which these operations are carried out.

SUMMARY OF THE INVENTION

According to an embodiment thereof, the present invention is a chassis for receiving a plurality of disk drives. The chassis may include a plurality of disk drive receiving stations, each disk drive station being configured to receive one of the plurality of disk drives and to carry out at least one of testing and servo writing operations on the received disk drive. Each disk drive receiving station may include a base; a nest assembly and a plurality of elastomeric mounts elastically coupling the nest assembly to the base so as to enable movement of the nest assembly relative to the base. The nest assembly may include a nest, the nest being configured to receive and mate with the disk drive and a printed circuit board attached to the nest, the printed circuit board being configured to control at least one of the testing and the servo writing operations. Each disk drive receiving station may include a separate vibration isolating mass coupled to the nest to isolate vibrations originating within the nest from being transmitted through the elastomeric mounts to other nests in the chassis and to isolate vibrations originating outside the nest from being transmitted through the elastomeric mounts to the nest assembly.

The vibration isolating mass may be greater than the aggregate mass of the nest, the printed circuit board and the disk drive, for example. The nest may have a first surface and a second surface that faces the base, and the vibration isolating mass may be attached to the second surface of the nest. The vibration isolating mass may include cast iron, for example. Other dense materials may also be used. For example, the amount of the vibration isolating mass may be selected to have a weight between 1 and 20 lbs. The vibration isolating mass may define a flat surface, and the nest may include injection molded plastic. The nest may be attached to the flat surface of the vibration isolating mass so as to increase the rigidity and reduce warping of the nest.

According to another embodiment thereof, the present invention is a disk drive receiving station for carrying out testing and/or servo writing operations on a disk drive. The disk drive receiving station may include a base, a nest assembly and a plurality of elastomeric mounts elastically coupling the nest assembly to the base so as to enable movement of the nest assembly relative to the base. The nest assembly may include a nest that is configured to receive and mate with the disk drive, a printed circuit board attached to the nest, the printed circuit board being configured to control at least one of the testing and the servo writing operations, and a vibration isolating mass coupled to the nest and disposed between the nest and the base. The vibration isolating mass is effective to at least partially isolate vibrations transmitted through the base to the nest assembly through the elastomeric mounts.

The vibration isolating mass may be greater than the aggregate mass of the nest, the printed circuit board and the disk drive. For example, the amount of the vibration isolating mass may be selected to have a weight between 1 and 20 lbs. The nest may define a first surface and a second surface that faces the base, and the vibration isolating mass may be attached to the second surface of the nest. The vibration isolating mass, for example, may include or be formed of cast iron. The vibration isolating mass may define a flat surface and the nest may include injection molded plastic. The nest may be attached to the flat surface of the vibration isolating mass so as to increase the rigidity and reduce warping of the nest.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2is an exploded view that shows a single disk drive receiving station200, according to an embodiment of the present invention.FIG. 3is an exploded view that shows further elements of the single disk drive receiving station ofFIG. 2. The disk drive receiving station200is configured to receive a single disk drive (such as shown inFIG. 1, for example) and to carry out testing and/or servo writing operations on the received disk drive. Considering nowFIGS. 2 and 3collectively, the depicted disk drive receiving station200may include a base202and a nest assembly. The nest assembly may include a nest302and a printed circuit board206. The nest assembly may be elastically coupled to the base202via a plurality of elastomeric mounts204. The elastomeric mounts204enable movement of the nest assembly relative to the base202. For example, the elastomeric mounts204may include rubber mounts or other viscoelastic elements that serve to dampen or dissipate energy from the vibrations originating from the nest assembly or from sources external to the nest assembly. As shown, the nest assembly is coupled to the base202through the plurality of elastomeric mounts204.

The nest302is designed and configured to receive and mate with the disk drive (as used herein, the phrase “disk drive” is defined to be or include the HDA144or an assembly comprising both the HDA144and the PCBA141). The nest302may include or may be formed of injection molded plastic. A locking mechanism303may also be provided to mechanically lock the disk drive into the nest302. A printed circuit board (PCB)206may be attached to the nest302. The printed circuit board206may be configured to control the testing operations of the disk drive and/or to control the servo writing operations to the magnetic disk of the disk drive mated to the nest302. The printed circuit board may (but need not) communicate with a host computer to carry out and/or schedule the required operations and/or tests. When the disk drive is mated and locked to the nest302, electrical contacts on the printed circuit board206make contact with corresponding electrical contacts on the disk drive100, to enable the printed circuit board to provide power and control signals to the drive's spindle motor113and/or to provide power and control signals to the drive's own printed circuit board141.

According to embodiments of the present invention, each disk drive receiving station200includes a vibration isolating mass304that is coupled (e.g., mechanically attached) to the nest302, between the nest302and the base202of the disk drive receiving station. The vibration isolating mass304is best shown inFIG. 3. The vibration isolating mass304helps in isolating the disk drive100from the higher frequency vibrations originating from outside the disk drive receiving station200and to at least partially isolate structures outside of the disk drive receiving station200from the higher frequency vibrations originating from within the nest302(such as, for example, vibrations from the HDA of the drive transmitted to the nest302). The vibration isolating mass304, therefore, operates to reduce the transmission of potentially drive damaging high frequency vibrations that are transmitted through the elastomeric mounts204to structures outside of the disk drive receiving station100and to reduce the transmission of any high frequency vibrations that originate from outside the disk drive receiving station that are transmitted through the elastomeric mounts204to the nest assembly—and to the drive100received within the nest assembly. In this manner, the combination of the elastomeric mounts204and the vibration isolating mass304serves to dissipate the energy and reduce the transmission of higher frequency vibrations originating within the nest assembly that are transmitted to structures outside of the nest assembly and also serves to reduce the transmission of the higher frequency vibrations originating from outside the nest assembly that are transmitted to the nest assembly. This has a beneficial effect upon the testing and/or servo writing operations carried out on the disk drive100mounted within the nest assembly. Reducing the transmission of and dissipating at least some of the energy of the transmitted vibrations also has a beneficial effect on any neighboring disk drive receiving stations and on the operations and/or tests performed therein.

According to an embodiment of the present invention, the vibration isolating mass304is greater than the aggregate mass of the nest302, the printed circuit board206and the disk drive100. For example, the vibration isolating mass304is greater than the aggregate mass of all of the other structures shown inFIG. 2. For example, the amount of the vibration isolating mass304may be selected to have a weight within the range of 1 to 20 lbs. According to an exemplary embodiment of the present invention, the amount of vibration isolating mass may be selected to have a weight within the range of 8 and 14 lbs. For example, the amount of vibration isolating mass304may be selected to have a weight of about 12 lbs. However, those of skill in this art may recognize that the amount of the vibration isolating mass may be selected to reduce the transmission of transmitted vibrations of predetermined frequencies and/or may be selected based upon empirical data. Embodiments of the present invention, therefore, are not to be limited to any value or range for the amount of the vibration isolating mass.

The vibration isolating mass may include or be formed of any suitably dense material. For example, the vibration isolating mass304may be formed of cast iron, as cast iron is readily available, inexpensive and may be cast into most any desired shape. The nest302may define a first surface configured to receive the disk drive100and may define a second surface that faces the base202. According to an embodiment of the present invention, the vibration isolating mass304may be attached to the second surface of the nest302, such that it is disposed between the nest302and the base202. As suggested inFIG. 3, the surface305of the vibration isolating mass304may be cast and/or machined to be very flat. As the injection molded nest302may warp and exhibit less rigidity than would be optimal, attaching the nest302to the flat surface305of the rigid, heavy and flat vibration isolating mass305advantageously reduces warping of the nest302and increases its the rigidity.

FIG. 4shows a chassis402that includes a plurality of disk drive receiving stations, according to an embodiment of the present invention. The chassis402may define a plurality of bays and each of the bays may contain a single disk drive receiving station such as shown inFIG. 2. The chassis402, in this manner, contains an array of disk drive receiving stations, each of which may be configured to perform test and/or servo writing operations on a disk drive100. The base202of each disk drive receiving station200may be secured (e.g., removably attached) within one of the bays of the chassis402. As the chassis402is a rigid structure, vibrations originating from outside of the chassis402may be transmitted to the individual disk drive receiving stations and to the respective disk drives mounted therein. Moreover, vibrations may originate from the constituent disk drive receiving stations and/or from the respective received disk drives and be transmitted to other, adjacent disk drive receiving stations and to the respective disk drives received therein. According to an embodiment of the present invention, each of the bays of the chassis402includes a single disk drive receiving station, and each such disk drive receiving station includes a separate vibration isolating mass, such as shown at304inFIGS. 2 and 3, disposed between the respective nests302and the respective bases202thereof.

Advantageously, the vibration isolating mass304serves to at least partially isolate the nest assembly from transmitting high frequency vibrations and to dissipate at least some of the energy of such vibrations. The large added mass of the vibration isolating mass304creates a nest assembly that is more massive than it otherwise would be. This large mass reacts less to outside vibrations by serving to reduce the amplitude of induced motion. Additionally, since the larger mass requires more energy to move in one direction, then stop, then reverse direction in cyclic vibration, it is more effective at screening out higher frequency vibrations, as the vibration isolating mass304cannot react fast enough to the forcing frequency of the vibration. In this manner, the added mass of the vibration isolating mass304at least partially isolates the nest assembly from the effects of higher frequency vibrations by reducing the transmission of higher frequency motion into the nest assembly. Similarly, the added mass of the vibration isolating mass304reduces the transmission of higher frequency vibrations from the floor on which the chassis rests or from the chassis to the contained disk drive receiving stations and reduces the transmission of higher frequency vibrations generated by moving HDA elements of the received disk drive within a given nest assembly to other nest assemblies and other received disk drives in the chassis402.