10 MILLIMETER FORM FACTOR FOR A 2.5 INCH DISK DRIVE

Abstract: A 10 millimeter z-height form factor is disclosed having a base plate (24) with a spin motor boss (26) for holding a spin motor (14) and an actuator bearing assembly boss for coupling an actuator bearing assembly. A circuit board (38) positioned below the base plate has a hole for receiving the spin motor boss (26) and a hole for receiving the actuator bearing assembly boss.

Description: 10 MILLIMETER FORM FACTOR FOR A 2.5 INCH DISK DRIVE FIELD OF THE INVENTION: The present invention pertains to the field of computer system disk drives. More particularly, this invention relates to an apparatus and method for minimizing the z- height form factor of a disk drive. BACKGROUND OF THE INVENTION: A recent trend in the computer industry is the development of smaller form factors for portable computers. Recently developed form factors include laptop computers, as well as notebook computers and palmtop computers. As such computers continue toward smaller form factors, the need for smaller form factor disk drives increases. Accordingly, computer manufacturers require lower z-height disk drives to further reduce portable computer form factors, and reduce the weight of portable computers. For example, a reduced z-height disk drive could be placed underneath the keyboard of a notebook or palmtop computer without causing an increase in the overall height of the computer. Nevertheless, a reduced z-height form factor disk drive must have a housing to contain mechanical components of the disk drive, as well accommodate a circuit board containing the disk drive electronics. However, there are several mechanical problems to overcome to achieve a lower z- height form factor for a disk drive. For example, the spin motor for the disk drive must be large enough to generate sufficient torque to overcome the frictional resistance caused by the read/write heads resting on the surfaces of the disk platter. However in prior disk drives, the relatively large z-height spin motors, and the bolts or screws that couple the spin motor to the disk drive base add excessively to the z- height form factor of the disk drive. Also, the z-heights of the voice coil motor and the actuator that positions the read/write heads must be minimized in order to achieve a lower z-height form factor for a disk drive. Further, prior art disk drives typically employ a clip located near the top of the actuator bearing assembly to hold the assembly sleeve on the actuator body and to limit vibration of the actuator body. In addition, a V-groove is typically formed near the top portion of the assembly sleeve in order to accommodate an external mechanism for initializing data tracks of the disk drive. However, placement of both the clip and V-groove near the top of the bearing assembly causes an increase in the height of the cover plate, thereby increasing the overall z-height form factor for the disk drive. SUMMARY AND OBJECTS OF THE INVENTION One object of the present invention is to minimize the z-height form factor for a disk drive. Another object of the present invention is to achieve a 10 millimeter form factor for a 2.5 inch disk drive while maintaining standard mounting configuration into a computer system. Another object of the present invention is to achieve a 10 millimeter z- height form factor for a disk drive, while employing a spin motor having sufficient torque to overcome the frictional resistance caused by the read/write heads of the disk drive resting on the surfaces of the disk platter. Another object of the present invention is to minimize the z-height of the actuator of the disk drive in order to achieve a 10 millimeter z- height form factor, while coupling plastic parts to the actuator with sufficient strength to withstand impact forces on the actuator. A further object of the present invention is to position an actuator bearing clip, and form a V-groove for coupling an external mechanism to the actuator for initializing the disk drive, in order to achieve a 10 millimeter z- height form factor for a disk drive. These and other objects of the invention are provided by a disk drive having base plate with a spin motor boss and an actuator bearing boss. A spin motor is bonded within the spin motor boss. The spin motor generates sufficient torque to overcome frictional resistance caused by the read/write heads resting on a disk platter. A bearing assembly sleeve of an actuator for positioning the read/write heads is coupled to a bearing assembly shaft disposed within the actuator bearing boss of the base plate. A circuit board having the disk drive electronics is positioned below the base plate. The circuit board has a hole for receiving the spin motor boss and a hole for receiving the actuator bearing boss. A connector recess is formed in the base plate, such that the connector recess accommodates coupling of an external connector to an edge connector of the circuit board. The bearing assembly and the actuator body are held together by a retainer ring positioned below the assembly sleeve. The assembly sleeve has a circular V-groove formed around an upper portion of the actuator pivot. The V-groove receives an external mechanism that positions the actuator during initialization of the disk drive. A latching member having pins is coupled to a precision machined shelf with two holes formed in the actuator body, such that the pins and the holes are aligned horizontally along the actuator body. The precision machined shelf provides alignment vertically in order to minimize the z-height form factor. Other objects, features and advantages of the present invention will be apparent from the accompanying drawings, and from the detailed description that follows below. BRIEF DESCRIPTION OF THE DRAWINGS The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements, and in which: Figure 1 shows a cross sectional side view of the mechanical components of a 2.5 inch disk drive having a 10 millimeter z-height form factor; Figure 2 shows a top view of the mechanical components disposed within the base plate, including the disk platter, the spin motor, the actuator and the voice coil motor, and the latching member; Figure 3 is a cross sectional side view illustrating the location of the spin motor disposed within the spin motor boss formed in the base plate; Figure 4 is a side view of the base plate showing the positions of the spin motor boss and the actuator bearing boss; Figure 5 is a bottom view of the base plate showing the positions of the spin motor boss and the actuator bearing boss, as well as a connector recess; Figure 6 is a bottom view of a circuit board that provides electronic components for the disk drive, and shows an edge connector for attaching an electrical connector; Figure 7 is a top view of the actuator illustrating the coupling of a plastic latching member to the thin metallic actuator in order to provide a coupling to withstand impact forces; Figure 8 is a side view of the actuator illustrating the coupling of the plastic latching member to the thin metallic actuator; Figure 9 is a cross sectional view of the actuator bearing assembly illustrating the coupling between the assembly shaft and the assembly sleeve, and shows the retaining clip position and the V-groove position. DETAILED DESCRIPTION Figure 1 shows a cross sectional side view of the mechanical components of a 2.5 inch disk drive 10 having a 10 millimeter z-height form factor. Mechanical components of the disk drive 10 are housed within a base plate 24 coupled to a cover plate 16. A spin motor 14 is disposed within a motor boss 26 formed in the base plate 24. A disk platter 12 is coupled to the spin motor 14, such that the spin motor 14 causes the disk platter 12 to rotate. For one embodiment, the 10 millimeter z-height is measured from the top of the cover plate 16 to the bottom of the feet 29. An actuator bearing assembly 20 is disposed within an actuator bearing boss 28 formed in the base plate 24. An actuator 18 is coupled to rotate about the actuator bearing assembly 20 via a retainer ring (not shown) in order to position the read/write heads over the surface of the disk platter 12. A voice coil motor (VCM) magnet 22 is shown positioned above the windings of a VCM portion of the actuator 18. For one embodiment, it is preferable that the cover plate 16 is constructed of stamped aluminum or stainless steel. The cover plate 16 and the base plate 24 are constructed of materials having similar thermal properties in order to prevent deformation of the base plate 24 resulting from temperature changes. Figure 2 shows a top view of the mechanical components disposed within the base plate 24. The disk platter 12 is shown mounted to the spin motor 14. The actuator 18 is coupled to rotate about the actuator bearing assembly 20 under control of a voice coil motor comprising the VCM magnet 22, the VCM windings 30, and a VCM return plate 32. The actuator 18 controls the positioning of a pair of read/write heads 34 located at the tip of the actuator 18. Figure 3 is a cross sectional side view illustrating the location of the spin motor 14 within the base plate 24. The spin motor 14 must meet resistance and torque requirements to overcome frictional resistance caused by the read/write heads 34 resting on the surfaces of the disk platter 12. Thus, the spin motor must be large enough to accommodate permanent magnets of sufficient size to generate the required torque, while meeting the overall z-height form factor of the disk drive 10. To accomplish the torque and z-height requirements, the spin motor 14 is recessed within the motor boss 26 formed in the base plate 24. As describe more fully below, the motor boss 26 protrudes through a hole in a circuit board positioned below the base plate 24, thereby minimizing overall z- height of the disk drive 10. Also, the spin motor 14 is designed to have a low form factor, and is bonded to the base plate 24 in order to obviate the need for bolts or screws which would otherwise add to the z-height of the disk drive 10. In a similar manner, the actuator bearing assembly 20 is recessed within the actuator bearing boss 28 formed in the base plate 24 in order to minimize the z-height of the disk drive 10. A portion of the actuator bearing boss 28 protrudes through a hole in the circuit board positioned below the base plate 24. The actuator bearing boss 28 enables positioning of the actuator 18 lower in the base plate 24. The lower position for the actuator 18 enables a lower profile for the cover plate 16, thereby minimizing overall z- height of the disk drive 10. For one embodiment, the base plate 24 has a flatness of 6/1000 of an inch, with no more than 1.5/1000 per inch variation across the length. Flatness is maintained because a bow in the base plate 24 would cause misalignment in the mechanical components referenced to the base plate 24. The tolerances inside the base plate 24 are plus or minus 4/1000 of an inch. The tolerances on the bottom side of the base plate 24 are plus or minus 6/1000 of an inch. Figures 4 and 5 provide two views of the base plate 24. Figure 4 is a side view of the base plate 24 showing the positions of the motor boss 26 and the actuator bearing boss 28. Figure 5 is a bottom view of the base plate 24 showing the positions of the motor boss 26 and the actuator bearing boss 28, the feet 29, as well as a connector recess 36. Figure 6 is a bottom view of a circuit board 38 that provides electronic components for the disk drive 10. The circuit board 38 includes an edge connector 40 for attaching an electrical connector (not shown) for electrical connection with the disk drive 10. The connector recess area 36 is formed in the base plate 24 in order to provide a clearance area for coupling the electrical connector to the edge connector 40. The connector recess area 36 provides clearance for the electrical connector, while minimizing the overall z- height form factor of the disk drive 10. A spin motor hole 42 and an actuator bearing hole 44 are formed in the circuit board 38. The spin motor hole 42 enables the spin motor boss 26 to protrude through the circuit board 38 when the disk drive 10 is fully assembled. Similarly, the actuator bearing hole 44 enables the actuator bearing boss 28 to protrude through the circuit board 38. The spin motor hole 42 and the actuator bearing hole 44 enable positioning of the circuit board 38 in order to minimize the overall z-height form factor of the disk drive 10. For one embodiment, it is preferable that the circuit board 38 have a height of 110/1000 of an inch in order to achieve the overall z-height form factor of the disk drive 10. Also, the height of components mounted on the circuit board 38 is restricted. In an alternative embodiment, components mounted on the circuit board 38 are accommodated by recesses formed on the bottom side of the base plate 24. The components are mounted to the side of the circuit board 38 facing the bottom of the base plate 24. Referring again to Figures 4 - 5, recesses 80 - 82 formed in the bottom of the base plate 24 provide clearance for the components on the circuit board 38. The recesses 80 - 82 provide circuit board layout options to compensate the layout restrictions caused by the spin motor hole 42 and the actuator bearing hole 44. Figures 7 and 8 illustrate the coupling of a latching member 50 to the actuator 18. For one embodiment, the actuator 18 is constructed of aluminum, and the latching member 50 is formed from plastic and bonded with an adhesive. The actuator 18 is thin because the portion of the actuator 18 containing the voice coil motor windings must fit within a gap formed by the VCM return plate 32, which in turn fits within the overall z-height form factor of the disk drive 10. The latching member 50 is provided with a pair of pins 52 for coupling to a shelf with two holes 54 formed in the actuator 18. The pins 52 and the shelf with two holes 54 are aligned horizontally along the actuator 18 in the plane of movement for the actuator 18. The coupling of the pins 52 to the shelf with two holes 54 using an adhesive provides sufficient strength to maintain coupling when the actuator 18 is subjected to impact forces. Figure 9 is a cross sectional view showing the coupling between the actuator bearing assembly shaft 20 and the assembly sleeve 19. An opening 62 enables coupling of the actuator bearing assembly to the base plate 24 via a screw (not shown). A retaining area 64 accommodates a retaining clip 71. The retaining clip 71 limits the vibration of the actuator body 18 and holds the actuator body 18 to the base plate 24. A V-groove 60 formed in the assembly sleeve 19 enables coupling of an external mechanism (not shown) for positioning the actuator 18. The external mechanism couples to the V-groove 60 to position the read/write heads 34 in order to initialize data tracks of the disk drive 10. By positioning the retaining area 64 on the bottom of the assembly sleeve 19 and positioning the V-groove 60 near the top of the assembly sleeve 19, the z-height of the cover plate 16 is reduced, thereby reducing the overall z-height of the disk drive 10. In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claims: CLAIMS What is claimed is: 1. A disk drive, comprising: base plate having a spin motor boss and an actuator bearing assembly boss; spin motor disposed within the spin motor boss, the spin motor coupled to rotate at least one disk platter; actuator comprising an actuator body and an actuator bearing assembly, the actuator bearing assembly disposed within the actuator bearing assembly boss; circuit board positioned below the base plate, the circuit board having a first hole for receiving the spin motor boss and a second hole for receiving the actuator bearing assembly boss. 2. The disk drive of claim 1 , wherein the spin motor is bonded within the spin motor boss. 3. The disk drive of claim 1 , further comprising latching member having at least one pin for coupling to a shelf with at least one hole formed in the actuator body, such that the pins and the holes are aligned horizontally along the actuator body. 4. The disk drive of claim 1 , wherein the circuit board has an edge connector for coupling to an external connector to provide electrical communication with the disk drive. 5. The disk drive of claim 4, wherein a connector recess is formed in the base plate, such that the connector recess accommodates coupling of the external connector to the edge connector of the circuit board. 6. The disk drive of claim 4, wherein at least one component recess is formed in the base plate, such that the component recesses accommodate high profile components on the circuit board. 7. The disk drive of claim 1 , wherein the actuator bearing assembly and the actuator body are held together by a retaining clip positioned below the actuator body. 8. The disk drive of claim 7, wherein the actuator bearing assembly has a circular V-groove formed around an upper portion of the actuator bearing assembly, the V-groove for receiving an external mechanism that positions the actuator during initialization of the disk drive. 9. The disk drive of claim 1 , further comprising a cover plate for coupling to the base plate to enclose the spin motor, the disk platter, and the actuator. 10. The disk drive of claim 9, wherein the cover plate has thermal properties substantially similar to the thermal properties of the base plate. 11. The disk drive of claim 10, wherein the cover plate comprises stamped aluminum or stainless steel. 12. The disk drive of claim 11 , wherein the disk drive has a z-height form factor substantially equal to 10 millimeters. 13. A method for minimizing the z-height of a disk drive, comprising the steps of: forming a spin motor boss and an actuator bearing assembly boss in a base plate for mounting mechanical components of the disk drive; bonding a spin motor within the spin motor boss, and coupling the spin motor to rotate at least one disk platter; coupling an actuator to an actuator bearing assembly; disposing the actuator bearing assembly within the actuator bearing assembly boss; coupling a circuit board having electronics for the disk drive below the base plate, the circuit board having a first hole for receiving the spin motor boss and a second hole for receiving the actuator bearing assembly boss. 14. The method of claim 13, further comprising the steps of: forming a shelf with at least one hole in the actuator body, the shelf with the holes aligned horizontally along the actuator body; coupling a latching member having at least one pin to the actuator body by inserting the pins into the holes, such that the pin and the shelf with the holes are aligned horizontally along the actuator body. 15. The method of claim 13, further comprising the steps of: forming a recess in the bottom of the base plate for receiving an external connector; coupling the external connector through the recess in the base plate to an edge connector of the circuit board to enable electrical connection with the disk drive. 16. The method of claim 13, further comprising the steps of: forming at least one component recess in the bottom of the base plate; positioning at least one high profile component on the circuit board such that the component recesses provide clearance for the high profile components. 17. The method of claim 13, further comprising the step of coupling a retaining clip between the actuator body and the actuator bearing assembly to limit vibration of the actuator, such that the retaining ring is positioned below the actuator body. 18. The method of claim 17, further comprising the step of forming a circular V-groove around an upper portion of the actuator bearing assembly, the V-groove for receiving an external mechanism that positions the actuator during initialization of the disk drive. 19. The method of claim 13, further comprising the steps of: forming a stamped cover plate from material having substantially similar thermal properties to the base plate; coupling the stamped cover plate to the base plate to enclose the spin motor, the disk platter, and the actuator.

Inventors: BAKER DAVID L, BOECKNER JAMES W JR, CHESSMAN SHIRLEY, SWENSON MARK, BAKER, DAVID, L., BOECKNER, JAMES, W., JR., CHESSMAN, SHIRLEY, SWENSON, MARK
Applicants: MAXTOR CORP, MAXTOR CORPORATION
Application year: 1993
Main classification: G11B5
IPC codes: G11B25, G11B33