JP2002536780A - Balanced disk spacer for hard disk drive - Google Patents

Abstract

(57) [Summary] An information processing apparatus such as a disk drive (100), comprising a base (112), a disk stack rotatably mounted on the base, and movably mounted on the base (112). An information processing apparatus including a selected actuator assembly. The disk stack assembly (200) includes a spindle hub (133) rotatably coupled to a disk drive. The disk stack assembly also includes a clamp, a disk spacer (210), and a disk coupled to the spindle hub. The disk spacer is asymmetric and is positioned to balance the mass offset of the disk stack assembly. The asymmetric disk spacer also includes an alignment surface (212).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to the field of mass storage devices. In particular, the invention relates to balancing a disk pack assembly about the axis of rotation of a disk spindle.

BACKGROUND OF THE INVENTION One of the key components of any computer device is a place where data is stored. Computer devices have a variety of locations where data can be stored.
One common place to store large amounts of data in a computer device is a disk drive. The most basic part of a disk drive is a rotating disk, actuators that move the transducer to various points on the disk, and electrical circuits used to write and read data to and from the disk. is there. Disk drives also include circuitry to encode the disk so that data can be successfully retrieved and written to the surface of the disk. The microprocessor controls most of the operation of the disk drive and returns data to the requesting computer, and retrieves data from the requesting computer for storage on disk.

[0003] Information representing data is stored on a surface of a memory disk. The disk drive reads and writes information recorded on tracks of a memory disk.
Transducers in the form of read / write heads mounted on sliders on both sides of the memory disk are provided when the transducer is positioned exactly on a designated track on the surface of the memory disk. Read and write information to
The transducer is also adapted to move to a target track. As the memory disk rotates and the read / write head is accurately positioned over the target track, the read / write head can store the data on the track by writing information representing the data onto the memory disk. . Similarly, reading data from the memory disk is accomplished by positioning the read / write head over the target track and reading the stored material on the memory disk. Read / Write to write to or read from various tracks
The write head moves radially across the track to the selected target track. The data is split or grouped together on a track. In some disk drives, a track is a number of concentric circular tracks. In other disk drives, a continuous spiral forms a track on one side of the disk drive. Servo feedback information is used to accurately position the transducer. The actuator assembly is moved to the required position and held very accurately during a read or write operation using the servo information.

[0004] The transducer is typically housed within a slider. The slider is a small ceramic block passed over the disk in transducing relation with the transducer. Small ceramic blocks, also called sliders, are usually aerodynamically configured to float over the disk. Most sliders have an air bearing surface ("ABS") that includes a rail and a cavity between the rails. As the disk rotates, air is pulled between the rails and the surface of the disk, creating a pressure that pushes the head away from the disk. At the same time, the air running through the air bearing cavity creates a negative pressure area.
The negative pressure or suction offsets the pressure generated at the rail. The slider is also mounted on a load spring that generates a force on the slider that guides the slider toward the disk surface. Various forces balance such that the slider flies over the surface of the disk at a particular flying height. The floating play height is the thickness of the air lubricating film, that is, the distance between the disk surface and the conversion head. This film eliminates friction and eliminates friction that would occur if the transducing head and the disk were in mechanical contact during rotation of the disk. In some disk drives, the slider passes through a layer of lubricant rather than floating above the surface of the disk.

When a disk is in operation, the disk typically has a relatively high rotational speed (“RPM”).
)). Today's normal rotational speed is 7200 RPM. The rotation speed of a high-performance disk drive is as high as about 10,000 RPM. Faster speeds are considered in the future. These high rotational speeds may result in shorter access times. In other words, as the disk rotates faster, the time required to access certain pieces of information in the drive is reduced, thus improving the performance of the disk drive. Shorter access times are always a goal for disk drive designers and manufacturers.

[0006] Higher rotational speeds also make disk drives more susceptible to vibrations due to unbalanced rotating parts. As a result, part of the assembly process typically involves balancing rotating members in a disk drive. The main rotating part in the disk drive is the disk stack assembly. The disk stack assembly consists of one or more disks fixed to a spindle. Disk spacers and clamps are used to attach the disk to the spindle hub. A spindle motor is used to rotate the hub and disk stack assembly.

[0007] Balancing disk packs is extremely important because unbalanced conditions can cause many problems in disk drives. One of the problems with unbalanced disc packs is that they vibrate and generate noise. Unbalanced disk packs also distort the bearing between the rotating part of the hub and the spindle shaft. The life of a distorted bearing is shorter than the standard life of a disk drive. Also, non-uniform disk packs will cause irregular speed fluctuations between the transducing head and the tracks on the disk. These speed variations can result in read / write errors. Variations in the plane and axial direction of the disk surface can also result in head failure.

[0008] Furthermore, the plane vibration, that is, the vibration traveling in the plane of the data surface of the disk, makes the track following ability of the transducer difficult. In other words, when the disk stack oscillates in the plane direction, the track to be followed moves laterally to the track following direction of the conversion head. The problem is magnified by the fact that the trucks are very close together. Track densities of 10,000 tracks per inch are common in today's disk drives. Six trucks are comparable to human hair. This problem will only get worse over time as higher track densities are planned for the future. That is, the performance of the disk drive is enhanced by packing the tracks closer together. The more tracks on a disc, the more information that can represent the data. Further, if the vibration mode has a higher frequency than the frequency at which the servo sector is read, the head may cross the track several times between servo sectors.

Prior attempts to solve the problem of unbalanced disk packs have attempted to center the rotational mass with respect to the rotational axis of the disk assembly so that the fit between the inner diameter of the disk and the outer shape of the hub is as tight as possible. To design and manufacture to tight tolerances. Since it was not possible to achieve a perfect fit and a uniformly balanced disc, this still resulted in an unbalanced condition. To achieve a better balance, a balance ring was used. Better balancing was obtained by adding or removing material from the balance ring as the delicate balancing device dictates, but it was a further step in the assembly of the disc pack. It was a price.

US Pat. No. 4,358,803 to Van Der Giessen discloses a precisely machined inner wall of the center opening of the disk and at least one of the inner walls for centering the disk. It describes centering elements that cooperate with the individual. US Patent No. 4,224,648 to Rolling
In No. 5, centering was performed by using a steel centering ball in the center of a disk pack having a hemispherical surface facing the spindle cup. Centering with respect to the inner wall of the disk does not ensure that the disk is centered with respect to the majority of the rotating mass of the disk located almost completely outside the inner wall of the disk. The outer diameter of the disc may not be completely concentric with the inner diameter of the disc. Thus, centering with respect to the inner diameter of the disk requires a high degree of precision in aligning the disk before fixing the disk to the hub, ignoring those that are a major source of unbalance. .

[0011] The foregoing method of centering and securing a disk to form a disk pack also results in the generation of particles, which degrades disk drive performance and even causes head crashes. It is possible. US Patent 4,35
No. 8,803, the machined inner wall and centering element of the center opening of the disc, and mating surfaces such as steel balls and spindle cups in US Pat. Designed to slide while participating. Such sliding generates undesirable particles.

A method of assembling another disk pack for use in a disk drive is disclosed in US Pat. No. 4,683, issued to Schmidt et al.
, 505. In U.S. Pat. No. 4,683,505, a disk pack has disks that are alternately diametrically deflected about the axis of rotation of the spindle. The discs are positioned so that the alternating opposing outer edges are aligned as if they were the outer edges of a centered nominal diameter disc. This results in an increase in the number of axial nodal points due to potential unbalanced inertia and a reduction in the amplitude of the associated vibration. Also, pairs of similar elements are diametrically deflected alternately about the axis of the spindle so that the disk spacers attempt to balance each other to minimize potential vibrations. The problem with this method is that it requires an even number of disks in the disk stack.
Further, the method does not work in a disk stack with one disk because there is no other disk balancing with only one disk. Many of the other methods require long cycle times, which are undesirable for manufacturing.

[0013] Thus, there is a need for a method and apparatus for balancing a disk pack having only one disk. There is also a need for a method that is easy to assemble and easy to manufacture. There is also a need for a method that does not generate particles.

An information processing apparatus, such as a disk drive, includes a base, a disk stack rotatably mounted on the base, and an actuator assembly movably mounted on the base. . The disk stack assembly includes a spindle hub rotatably coupled to the disk drive. The spindle hub has a rotation axis about which the disk stack assembly rotates. The spindle hub includes a tubular portion. The disk stack assembly also includes a clamp, a disk spacer, and a disk coupled to the spindle hub. The disc spacer has an opening therein sized to receive the cylindrical portion of the spindle hub. The disk spacer is asymmetric and is positioned to balance the mass offset in the disk stack assembly. The asymmetric disk spacer also includes an alignment surface. The alignment surface is located on the outer periphery of the disk spacer. The disk spacer has a center of mass offset from the axial centerline of the opening. Disc spacers are used to offset the offset center of mass of the disc stack assembly. Typically, balancing the disk stack assembly means that the center of mass of the spacer is on one side of the axis of rotation of the hub and the center of mass of the disk stack assembly is on the other side of the axis of rotation of the hub. There is a need. The flat surface of the asymmetric disk spacer is located such that the flat surface intersects the plane defined by the axial centerline of the disk stack assembly and the point associated with the mass offset of the disk assembly. .

[0015] Asymmetric disk spacers may be advantageously used to balance disk stacks having only one disk. Further, asymmetric disk spacers can also be used to balance disk stacks with multiple disks. This method is easy to use. This facilitates assembly and the manufacturing process. The method also minimizes particles generated because the disk clamp is not machined during the balancing process and the flat side is formed as a mating surface. The flat side provides a simple but effective way to allow the tool that deflects the disk spacer to engage its surface while automatically aligning the spacer in the desired direction. Asymmetric disk spacers also minimize material waste and reduce the cost of the component.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. . It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.

The invention described in this patent application is useful for all mechanical forms of disk drives having either rotary or linear operation. Furthermore, the present invention also covers all types of disk drives, including hard disk drives, zip drives, floppy disk drives, and any other type in which it is desirable to unload the transducer from one side or park the transducer. It is also useful in drives. FIG. 1 is an exploded view of one type of a disk drive 100 having a rotary actuator. Disk drive 100 includes a housing or base 112 and a cover 114. The base 112 and the cover 114 form a disk seal. The actuator assembly 120 includes an actuator shaft 118 and a base 112.
It is rotatably mounted on. The actuator assembly 120 includes a plurality of arms 12.
3 is included. Load beams or load springs 124 are attached to the individual arms 123 of the comb structure 122. The load beam or spring is also called a suspension. At the end of each load spring 124, a slider 126 carrying a magnetic transducer 150 is mounted. The slider 126, together with the transducer 150, forms what is often referred to as a head. It should be noted that many sliders have one transducer 150, which is shown in the figure. The present invention also relates to a method referred to as MR, i.e., one or more transducers, such as a magnetoresistive head, where one transducer 150 is generally used for reading and another transducer is commonly used for writing. It should be noted that the invention is equally applicable to sliders having a cavity. On the side of the actuator arm assembly 120 opposite the load spring 124 and the slider 126 is a voice coil 128.

A pair of magnets 130 are mounted in the base 112. A pair of magnets 13
Zero and voice coil 128 are the core elements of a voice coil motor that provides a force to rotate actuator assembly 120 about actuator shaft 118. The base 112 is also provided with a spindle motor. The spindle motor includes a rotating part called a spindle hub 133. In this particular disk drive, the spindle motor is in the hub. In FIG. 1, a number of disks 134 are mounted on a spindle hub 133. In other disk drives, a single disk or any number of disks may be mounted on the hub. The invention described herein is equally applicable to disk drives having multiple drives as well as disk drives having a single disk.

FIG. 2 is a side view of a spindle hub 133 having a plurality of mounted disks 134 and a plurality of disk spacers 210 forming a disk stack assembly 200. Disk stack assembly 200 also includes disk 134 and spacer 2.
10 and a disk clamp 220 for attaching the hub to the hub 133. Hub 133 includes a mounting flange 233. Initially, spacer 210 is located on mounting flange 233. Thereafter, the disk 134 is located on the spindle hub 133. Once a selected number of disks 134 and spacers 210 are located on spindle hub 133, a disk clamp is used to axially load the disks and disk spacers and attach them to spindle hub 133. In this particular embodiment, disk clamp 220 is a screw-type disk clamp. As shown in FIG. 2, the disk spacer 210 includes a flat surface 212. The flat surface 212 acts as a tool alignment surface, a means used to balance the disk stack assembly 200 during manufacturing. The flat surface 212 also makes the spacer ring 210 appear physically asymmetric. As shown in FIG. 2, the spacer ring 210 includes a disk stack assembly 20 including a plurality of disks 134.
0 is available.

FIG. 3 is a side view of the spindle hub 133 on which the single disk 134 and the single disk spacer 210 are mounted. Disk stack assembly 200 shown in FIG.
Indicates that the spacer 210 can be used in a disk drive configuration with a single disk 134. Disk 134 is located on hub 133 and against mounting flange 233 of hub 133. Next, the spacer 210 is located on the disk 134 and around the hub 133. Next, a clamp 220 is used to hold the disk 134 and the disk spacer 210 against the hub,
It is also used to apply an axial force to the disk spacer 210 and the hub 133. The use of asymmetric spacers 210 is also extremely useful in balancing disk stacks containing a single disk, such as the disk stack shown in FIG.

FIG. 4 is a perspective view of a disk spacer ring 210 having a flat surface 212. Disc spacer 210 includes an annular body 400 and a lip 402. Annular body 400 includes an inner diameter 410 and an outer diameter 412. Annular body 400 also has an axial centerline 420. Flat surface 212 is formed from a portion of lip 402 of spacer 210. It is contemplated that the flat surface 212 may extend to form a flat at the outer diameter 412 of the annular body 400. The position of the flat surface 212 will vary depending on the center of mass, i.e., how much the designer wants the center of gravity to shift the axial centerline of the disk spacer. The amount of shift depends on the design of the disk drive and the factors used in the disk stack assembly 200.

Referring now to FIGS. 5 and 6, the offset between the center of gravity, ie, the center of mass, and the axial centerline of the disk spacer 210 is shown. FIG. 5 is a top view of the asymmetric spacer ring 210. FIG. 6 is a side cross-sectional view of the asymmetric spacer ring 210 taken along line 6-6 in FIG. The center of gravity, or center of mass, of the disk spacer ring 210 is designated by the reference numeral 500. As can be seen, the center of gravity or center of mass 500 is the axial centerline 420 of the disc spacer 210.
The center of gravity 500 is asymmetrically shifted from the axial center line 420 in a direction away from the flat surface 212 of the disk spacer 210. Thus, the physical asymmetry also shifts the center of mass or center of gravity 500 away from the axial centerline of the disk spacer 210. This can be expressed as forming a bias direction of the mass or biasing the mass away from the axial center line of the disk spacer 210. The direction of mass shift is a direction away from the flat portion 212 of the disk spacer 210.

FIG. 7 is a perspective view of the spindle hub 133 on which the disk 134 is mounted, forming the disk stack assembly 200. The disk 134 has a mounting flange 233.
, Hub 133, disk spacer 210 and disk clamp 220 have been disassembled and removed for clarity. The spindle assembly 200 also has an axial centerline 720. Typically, the axial centerline 720 corresponds to the rotation axis of the spindle hub 133 or the rotation axis of the entire disc stack assembly 200.

FIG. 7 also shows a first deflection direction 700 and a second deflection direction 710.
The first deflection direction 700 is associated with the displacement of the center of gravity from the axial centerline 420 of the disk spacer. In other words, the first deflection direction 700 is the direction of the disk spacer 2.
This is the direction in which the center of gravity 500 is shifted with respect to 10. The second deflection direction 710 is a shift in the center of gravity from the axial centerline of the disk stack assembly 200 due to the inherent unbalance of the members forming the disk stack assembly 200. The second deflection direction 710 is also determined by the disc 134, the hub 133, and the disc clamp 2
It can be attributed to 20 unbalances. The imbalance of these assembled components causes the center of gravity of the disk stack assembly 200 to move in the second deflection direction 710.
Is shifted from the center line 720 in the axial direction.

As can be seen from FIG. 7, the second deflection direction 710 is exactly opposite to the first deflection direction 700. In other words, the imbalance of the disk stack assembly 200 is offset by the imbalance of the disk spacer 210. In a disk drive using a single disk spacer, the unbalance is offset by a shift in the center of mass in a single spacer ring 210. In other words, this is offset by a mass unbalance or shift of the center of gravity from the centerline 420 access to a similar shift in the disk stack assembly 200. As shown in FIG. 7, the disk spacer 210 is mounted on the disk stack assembly 200.
It is positioned to balance the offset of the mass.

When the flat surface 210 is formed such that it includes a tangent to the inner or outer diameter of the disk spacer, an interesting relationship is formed that may be useful in the balancing process. Once the mass offset of the spindle assembly is detected, a plane can be formed that includes the centerline access 720 of the disk stack assembly 200 and the center of gravity of the disk stack assembly. By moving the disk spacer 210 to a position where the center of mass of the disk assembly is balanced by the shift of the center of mass of the disk spacer ring, the flat surface 212 is aligned with the axial centerline of the disk stack assembly 200 and the disk stack assembly 200. Will intersect with the plane defined by the point associated with the mass offset. Flat surface is disk spacer ring 21
2 includes a tangent to the inside or outside diameter, the flat surface is essentially a plane defined by the center line of the disk stack assembly 200 and the point containing the offset of the mass of the disk stack assembly. Perpendicular to

FIG. 8 shows the construction of a disk stack assembly 200 and the disk stack assembly 20.
6 is a flowchart of a method for balancing 0s. In operation, the machine that assembles the disk stack assembly first positions the spacer 210 and then the reference numeral 8 respectively.
Disk 134 is positioned on spacer 210 of hub 133 as shown at 00 and 810. The disk spacer 210 is located in a direction very close to the final direction by an automatic machine as indicated by reference numeral 820. Disk 200 is located on top of spacer 210 by an automatic machine. A deflection fixture associated with the automatic machine deflects the flat side of the disk spacer 210 in a first direction, as indicated by reference numeral 830. The deflection fixture also deflects the disk 134 in the opposite direction, as indicated by reference numeral 840. As the deflection fixture pushes against the flat side of the disk spacer 210, the disk spacer 210 itself aligns in an optimal direction. This deflects the spacer 210 and the disk 134. Next, reference number 8
The clamp 220 is mounted as indicated at 50. After tightening the disc 134 and the spacer 210 to the hub 133, a balance check is performed as indicated by reference numeral 860.

Asymmetric disk spacers can be advantageously used to balance a disk stack having only one disk. Further, asymmetric disk spacers can also be used to balance disk stacks having multiple disks. The method is easy to use. This simplifies assembly and the manufacturing process. The method also produces minimal particles because the disk clamp is not machined during the balancing process and is formed with the flat side as the mating surface. The flat side provides a simple but effective way in which the tool performing the deflection of the disk spacer can engage the surface and at the same time automatically align the spacer in the desired direction.
Asymmetric disc spacers also minimize material waste, thus reducing the cost of the component.

FIG. 9 is a schematic diagram of a computer device. The present invention relates to a computer device 1000.
Advantageously well adapted for use in The computer device 1000
It may also be called an electronic device or an information processing device, and includes a central processing unit, a memory, and a device bus. The information processing device includes a central processing unit 1004, a random access memory 1032, and a system bus 1030 that communicatively couples the central processing unit 1004 and the random access memory 1032. The information processing device 1002 includes a disk drive device including the above-described ramp (tilt). The information processing apparatus 1002 also includes an input / output bus 1010, for example, 1012, 1014, 1016, 10
Several peripheral devices, such as 18, 1020, 1022, can be attached to the input / output bus 1010. Peripherals may include hard disks, magneto-optical drives, floppy disk drives, monitors, keyboards, and other such peripherals. Any type of disk drive may use a slider that has been subjected to the surface treatment described above.

It is to be understood that the above description is illustrative and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

[Brief description of the drawings]

FIG. 1 is an exploded view of a disk drive with a stack of multiple disks and a ramp assembly for loading and unloading transducers to and from the surface of the disk.

FIG. 2 is a side view of a spindle hub with a plurality of mounted disks and a plurality of disk spacers forming a disk stack assembly.

FIG. 3 is a side view of a spindle hub with a single mounted disk and a disk spacer forming a disk stack assembly.

FIG. 4 is a perspective view of a disk spacer ring.

FIG. 5 is a top view of an asymmetric spacer ring.

6 is a cross-sectional view of the asymmetric spacer ring, taken along line 6-6 of FIG.

FIG. 7 is a perspective view of a spindle hub on which disks forming a disk stack assembly are mounted.

FIG. 8 is a flowchart of a method for balancing a disk stack.

FIG. 9 is a schematic diagram of a computer device.

[Procedure amendment]

[Submission date] August 21, 2001 (2001.8.21)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Contents of correction]

[Claims]

Claims3The disk stack has an axial centerline and the non-pair
The flat surface of the nominally shaped disc spacer isLocated so that it intersects the plane, Said plane Disc stack axial centerlineWhenThe diskOfOffset of mass Including Claims characterized by the following:1The disk used for the disk drive described in
Stack stack assembly.

Wherein said disk stack having a center line in the axial direction of the disc stack, wherein the planar surface of the disc spacer asymmetrical it is positioned so as to be orthogonal to the plane substantially, said planar disk according to claim 1, characterized in that it comprises a deviation in the axial direction of the center line and the disks of the mass of the disc stack of the stack assembly, the disk stack assembly for use in a disk drive.

5. A according to claim 1, wherein the asymmetrical disc spacer is positioned so balance the offset of the mass of the disk, the disk stack assembly for use in a disk drive.

It includes wherein offset the asymmetrical disc spacer is mass, to claim 1 where the disk spacer of the asymmetric shaped and being located so as to balance the offset of the mass of the disk A disc stack assembly for use in a disc drive as described.

7. A disk spacer center of mass of the spacer is on one side of the rotational axis of the hub, the quality of the amount hearts of the other portions of said disk stack assembly is on the other side of the axis of rotation of the hub The disk drive according to claim 1 , wherein:

8. that the mating faces such quality in amounts heart to position the said disc spacer so as to offset the center of offset of the mass of the other parts of the disc stack assembly of the disk spacers are used The disk drive according to claim 1 , wherein:

Claims910. The method of claim 1, further comprising a plurality of disk spacers. 8 A disk drive as described in.

10. The disk drive according to claim 9 , further comprising a plurality of disks.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventors Quak, Ben, We Win-Hun Mansion, Singapore, Gayland Lower 14, 12, Number 07-10 (72) Inventors Row, Chi, Suan Choa Chu, Singapore Can Avenue 2, Block 287, Number 08-195 F term (reference) 5D109 DA20 5D138 UA12 UA25

Claims (19)

[Claims] 1. A disk stack assembly for use in a disk drive, wherein the disk stack assembly rotates within the disk drive, wherein the disk stack assembly rotates the disk drive to provide an axis about which to rotate. A spindle hub operatively coupled and including a generally cylindrical portion; a clamp; an asymmetric disc spacer having an opening sized to receive the cylindrical portion of the spindle hub; and a hub coupled to the hub. A disk stack assembly comprising: a disk; and wherein the disk spacers are positioned to balance the mass of the stack assembly. 2. The disk stack assembly of claim 1, wherein the asymmetric disk spacer includes an alignment surface. 3. The disk stack assembly according to claim 1, wherein the asymmetric disk spacer includes a flat surface on an outer periphery of the spacer. 4. The disk stack has an axial centerline, and the flat surface of the asymmetric disk spacer is a plane defined by the axial centerline of the disk stack assembly. 4. The disk stack assembly for use in a disk drive according to claim 3, wherein the disk stack assembly is located so as to intersect a point related to the offset of the mass of the disk assembly. 5. The disk stack has an axial centerline, and the flat surface of the asymmetric disk spacer is offset from the axial centerline of the disk stack assembly by the mass of the disk assembly. 4. The disk stack assembly for use in a disk drive according to claim 3, wherein the disk stack assembly is positioned substantially perpendicular to a plane defined by points associated with the disk drive. 6. The disk stack assembly for use in a disk drive according to claim 1, wherein the asymmetric disk spacer is positioned to balance the offset of the mass of the disk. 7. The disk drive of claim 1, wherein the asymmetric disk spacer includes a mass offset and the asymmetric disk spacer is positioned to balance the mass offset of the disk. Disk stack assembly for use with. 8. A disk drive for use in a disk drive, the disk drive including a disk stack assembly rotating within the disk drive, wherein the disk stack assembly is a spindle hub rotatably coupled to the disk drive. A spindle hub rotating about an axis and including a generally cylindrical portion; a clamp; and a disk coupled to the hub, wherein the disk stack assembly is configured to rotate from an axis about which the spindle hub rotates. Means for offsetting the center of mass of the disk stack assembly with the disk spacer being positioned to balance the center of mass of the disk stack assembly. A disk drive including a disk stack assembly, further comprising: 9. An opening sized to receive the cylindrical portion of the spindle hub, wherein the means for offsetting the offset center of mass of the disk stack assembly is an opening having an axial centerline. 9. The disk drive of claim 8, wherein the disk spacer has a center that is offset in mass from an axial centerline of the opening. 10. The disk drive of claim 9, wherein the center of mass of the disk spacer is opposite to the center of mass of the disk stack assembly. 11. The center of mass of the spacer is on one side of the axis of rotation of the hub and the center of mass of the disk stack assembly is on the other side of the axis of rotation of the hub. Item 10. The disk drive according to item 9. 12. The disk drive according to claim 9, wherein said disk spacer includes an alignment surface. 13. The method of claim 1, wherein the alignment surface includes a flat portion.
3. The disk drive according to 2. 14. The alignment surface is used to position the disk spacer such that the center of mass offset of the spacer offsets the center of mass offset of the disk stack assembly. The disk drive according to claim 12, wherein 15. The disk drive according to claim 8, further comprising a plurality of disk spacers. 16. The disk drive according to claim 15, further comprising a plurality of disks. 17. A method of assembling a disk stack having a spindle hub, at least one disk, and an asymmetric spacer ring having a machine alignment surface, wherein at least one disk is movable about the spindle hub. Positioning the at least one disk on the hub; and pressing a mechanical alignment surface of the disk spacer ring. A method of assembling a disk stack and a spacer ring. 18. The method of claim 17, wherein pressing the mechanical alignment surface of the disk spacer ring shifts the weight imbalance of the asymmetric spacer ring. 19. The apparatus of claim 19, wherein the mechanical alignment surface of the spacer ring shifts the weight imbalance of the spacer ring to offset the weight imbalance of the hub and the at least one disk. 19. The method according to 18.