EP0530217A4

EP0530217A4 - Thin line micro hard disk architecture

Info

Publication number: EP0530217A4
Application number: EP19910908438
Authority: EP
Inventors: Frederick M. Stefansky; Bernard A. Russick; Glade N. Bagnell; Steven R. Speckman
Original assignee: Conner Peripherals Inc
Current assignee: Seagate Technology LLC
Priority date: 1990-05-23
Filing date: 1991-04-02
Publication date: 1993-09-08
Also published as: WO1991018390A1; EP0530217A1

Abstract

A disk drive (10) having dimensions of 5.15 inches long, 4.00 inches wide, and 0.805 inch high is provided. The disk drive (10) includes a cover (14) engaging a base (12) to form therebetween a controlled environment isolated from ambient atmosphere conditions. A storage medium, comprising a single magnetic plated disk (22) having a central point (21) to a plurality of concentric tracks, is rotatably mounted on said base (12) within the controlled environment. A means (20) for rotating the storage means about an axis passing through its center point, preferably comprising a spindle motor (20), is also mounted on said base (12). Transducers (60), one per disk surface, for reading and writing information to the disk (22), are mounted on an actuator (50) which positions the transducers (60) over selected, individual, concentric tracks on the disk (22). A printed circuit board (PCB) (15) provides control signals to the spindle motor (20), transducers (60), and the actuator (50) to selectively access the stored data.

Description

THIN LINE MICRO HARD DISK ARCHITECTURE

CROSS-REFERENCE TO RELATED APPLICATIONS "Magnetic Parking Device for Disk Drive," Serial No. 269,873, filed November 10, 1988, assigned to the assignee of the present application;

"Disk Drive System Using Multiple Embedded Quadrature Servo Fields," Serial No. 386,504, filed July 27, 1989, assigned to the assignee of the present application; and

"Low Height Disk Drive," Serial No. 147,804, filed January 25, 1988, assigned to the assignee of the present application. Each of these related applications is hereby incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to disk drives; more particularly, to disk drives which have increased storage capacity and reduced size, weight, and power consumption.

Description of the Related Art

The increasing use and popularity of portable and laptop computers has led those involved with data storage technology to develop devices with increased data storage capacity having decreasing weight, size, and power consumption. However, high reliability and device lifetime must be maintained. This trend in data storage is evidenced by a hard disk drive manufactured by the Assignee of the subject Application having a 3-1/2 inch form factor, a height of less than one inch, and data storage capacities of 20Mb and 40Mb in varying embodiments. This trend is further demonstrated by a hard disk drive manufactured by JVC Corporation having dimensions of 5.75 inches x 4.00 inches x 0.82 inch, with a storage capacity of approximately 42 Mbytes.

Disk drive manufacturers and computer manufacturers usually establish standards for vibration and shock resistance for hard disk drives. Among the criteria imposed on hard disk drives are vibration resistance, compactness, low weight, low power, and ease of manufacture. All of these criteria are usually important to a computer manufacturer selecting a disk drive for use in a specific computer or for a specific type of application. The standards may be more stringent for disk drives intended for use in portable or lap-top computers or other harsh environments where the drive is continually subjected to shock and vibration during transport.

One effect of vibrations applied to a disk drive, and one cause of errors in seeking and/or track following, is mechanical off-tracking, i.e., an unintended physical movement of the heads with respect to the disk(s). Mechanical off-tracking may be caused by movements of various structural components of the disk drive with respect to the disks.

Conventional disk drives have been fabricated of dense, heavy materials to provide the structural rigidity necessary to prevent thermal gradients and other physical stresses from causing mechanical off- tracking, making it difficult to reduce the size and weight of such disk drives. Further, existing disk drives incorporate a large number of mechanical parts; a large number of components presents problems in satisfying requirements for shock and vibration resistance.

The reduction in size of disk drives involves more that merely reducing the size of the numerous components used therein. In a number of cases, a re-arrangement of the drive architecture is required to achieve the desired form factor. Each re-arrangement of the components in a drive's architecture in itself leads to a new set of problems. To further increase a particular drive's resistance to physical shock, conventional hard disk drives often incorporate a device for parking the head(s) of the drive. As used in this patent, the terms "park" and "parking" refer to maintaining the position of the read/write heads over a selected, non-data storage portion (usually termed a "landing zone" and located at the inside or outside diameter) of the disk by latching the actuator which supports the heads. Many parking devices park the heads by physically engaging or "latching" the actuator. (The terms "latched" and "unlatched," respectively, refer to the engagement and disengagement of the parking device and the actuator.) It is desirable to park the actuator because physical shocks experienced during shipping or other non- operational movements of a disk drive may cause the head to "slap" against the disk, possibly causing a loss of data if the head slaps against a data-carrying portion of the disk. Parking the head assures that the head will land on the landing zone and will be held in a position over the landing zone during the power down period.

Electromagnetic parking devices require electrical power to release the parking device during operation of the disk drive which reduces the life of the batteries in a portable computer. Purely magnetic parking devices park the actuator by the attraction of and, generally, direct contact between a magnetically permeable portion of the actuator and a magnet. The primary drawback of a magnetic latch of this type is that during operation of the disk drive the rotational movement of the actuator is adversely affected by the attraction of the magnetically permeable portion of the actuator and the magnet, thereby creating problems with the track following and seek functions. Further, an extremely large force is required to release the actuator from the magnet. Another problem with prior disk drives is the difficulty in sealing the drive to protect the disks from contaminants. This difficulty arises from the large area which must be sealed to protect the environment where the disk resides and from the large number of points at which access is provided to the environment in which the disk resides. These access points are utilized to bring to the interior of the disk drive electrical circuits which provide current to the motor which rotates the disk, transmit data signals to and from heads which read and record information on the disks, and in some instances, provide current to a voice coil for positioning the heads with respect to the disk or disks.

SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a disk drive having reduced physical dimensions and reduced weight with a data storage capacity equivalent to drives having larger physical dimensions.

A further object of the invention is to provide a disk drive having a reduced total area, including a length shorter than that of conventional 3.5" form factor disk drives.

A further object of the invention is to provide a disk drive having an assembled height of less than eight-tenths of one inch, and preferably 0.75 inch.

A further object of the invention is to provide the above objects of the invention in a disk drive having an increased storage capacity and utilizing a single platter storage medium. These and other objects of the invention are accomplished by a disk drive having a base and cover, each having a length of 5.15 inches and a width of 4.00 inches. The cover engages the base to form a controlled environment isolated from ambient atmosphere conditions therebetween. A storage medium having a plurality of concentric tracks is rotatably mounted on said base within the controlled environment. A means for rotating the storage means, preferably comprising a spindle motor, is also mounted on said base. Transducer means for reading information from and writing information to said storage means are mounted on an actuator means for positioning the transducer means over selected, individual concentric tracks on said base. A control means for providing control signals to the means for rotating said disk drive, the transducer means, and the actuator means. When assembled, the total height of the disk drive does not exceed eight-tenths of one inch. A single data storage disk has a diameter of approximately 3.74 inches (a "so called" 3-1/2 inch disk), and a storage capacity of 85Mb. The drive has an overall height of 0.75 inch.

The actuator means includes an actuator arm having transducer means mounted thereon and moving in a plane substantially parallel to the plane defined by the disk. The actuator means is responsive to the control signals for positioning the read/write heads at specific locations on the disk. The actuator means rotates about an actuator pivot point which is approximately 2.2 inches from the central point of the disk. Preferably, the actuator arm may be cast of magnesium. The actuator means further includes a magnet and coil assembly mounted parallel to the base plate for providing a magnetic field to position the actuator arm and transducer assembly. Further, the actuator means includes a magnetically permeable capture member, mounted on a second actuator arm arranged perpendicularly to the first actuator arm, and a magnetic parking means for capturing the magnetic capture member to park the transducer means over a landing zone provided on the disk. Also included is a means for electrically interconnecting the control means, transducer means, and actuator to a printed circuit board assembly mounted under the base plate. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an exploded, isometric view of the base, cover, and printed circuit board of a disk drive according to the present invention;

Fig. 2 is a top-level plan view of a disk drive according to the present invention;

Fig. 3A is a cross-sectional side view along line 3-3 in Fig. 2;

Fig. 3B is an exploded view of the actuator mounting assembly;

Fig. 4 is a cross-sectional side view along line 4-4 in Fig. 2; and Fig. 5 is an exploded, isometric view of the actuator arm and actuator assembly of a disk drive in accordance with the present invention.

Fig. 6 is a cross-sectional view along line 6-6 in Fig. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Disk drives according to the present invention will be described herein with reference to Figs. 1-6. As discussed more specifically below, the preferred embodiment of the disk drive of the present invention includes a single hard disk with magnetic coating and utilizes Winchester storage technology; however, it is within contemplation of the present invention to utilize various numbers of disks and other types of disks such as optical disks, and other read/write technologies such as lasers.

The disk drives of the present invention reflect the continuing trend in the storage technology industry to incorporate a greater amount of data storage into ever- decreasing physical space dimensions, under a maximum of operating temperatures and shock conditions. The disk drives accomplish these objectives by providing a novel arrangement of traditional disk drive components. In the development of the ever-decreasing dimensions of hard disk drive, eight inch (8") form factor disk drives were followed by five and one-quarter inch (5-1/4") form factor disk drives. The length of a 5-1/4" form factor disk drive is approximately one-half of the length of an 8" form factor drive. This same size relationship applies to so-called three and one-half inch (3-1/2") form factor drives in relation to 5-1/4" drives--i.e. , a 3-1/2" form factor drive is approximately one-half the size of a 5-1/4" drive.

In the disk drives of the present invention, a so- called 3-1/2 inch disk having a diameter of approximately 3.74" (92mm) is utilized to provide a disk drive having a length of 5.15 inches, a width of 4 inches; one embodiment of these disk drive has an assembled height of 0.75 inch, and another embodiment has an assembled height of 0.78 inch. The total weight of the drives is less than one pound. The overall power consumption during the read and write functions is approximately 3.5 watts and power consumption may be as low as 1.5 watts during idle periods. Thus, these disk drives are ideal for use in portable, laptop, or other battery-powered computers. In particular, the 3/4" height of one of the disk drives of the present invention is approximately one-half of the disk drive height of a conventional 3-1/2" form factor hard disk drive, thereby allowing two of the drives of the present invention to occupy the space formerly occupied by a standard-height 3-1/2" form factor disk drive.

It is notable that the length of the disk drive of the present invention is approximately one-half of one inch (1/2") shorter than the length traditionally associated with hard disk drives utilizing 3-1/2" diameter disks. One reason for this reduction in length of the disk drive of the present invention is the desire on the part of the inventors to provide a hard disk drive which could be used in place of commerically available floppy disk drives having a 5.15" length and 4" width. With reference to Figs. 1-6, a disk drive 10 in accordance with the present invention includes a base 12 and cover 14 comprised of, for example, aluminum. A gasket 16 is provided between base 12 and cover 14 to establish a sealed (or controlled) environment between base 12 and cover 14. The cover 14 is mounted on base 12 by means of socket head screws (not shown) provided through bores 18 in cover 14 to screw into threaded mounting holes 19 to attach the cover 14 to base 12. The positioning of bores 18 on the cover 14 and the threaded mounting holes 19 on base 12 are such as to enhance the structural rigidity of the drive 10.

Other features of disk drive 10 include actuator assembly 50, spindle motor 20, and printed circuit board (PCB) 15. The PCB 15 contains circuitry for providing control signals necessary for operating the disk drive. As is shown more particularly in Figs. 2 and 3A, the disk drive 10 further includes a disk 22 mounted on spindle motor 20 to provide a means for storing data in the drive.

A header assembly 25, comprising a plurality of holes 26 and a corresponding plurality of pins 28 press- fit into the holes 26, transfers control signals from PCB 15 to the controlled environment within base 12 and cover 14. Pins 28 of header assembly 25 plug directly into a connector 27 provided on PCB 15. As is shown in Fig. 1, the structure of base 12 and PCB 15 is such that a minimum amount of height is required to provide a mounting area for the plurality of components utilized in the drive. In general, base 12 is provided with a flat top surface for conveniently mounting the components of the disk drive thereon during the manufacturing process. This type of base significantly increases the speed with which the drives can be manufactured over conventional drives using a base having the so-called "bathtub" design. A base having the bathtub design requires that elements being mounted to the base and the tools used to mount the elements must all fit within the walls of the bathtub, making it difficult to locate an element and later rotate the element into position. Base 12 includes recess 13 in which the actuator assembly 50 is mounted. Base 12 also includes a well region 17 for receiving spindle motor 20.

PCB 15 mounts on the bottom of base 12 in a configuration such that the circuitry provided on PCB 15 does not extend beyond the total height of side rails C and D of base 12. As discussed more completely below, the circuitry provided on PCB 15 creates control signals which control, for example, the operation of the actuator assembly 50 and spindle motor 20 to allow disk drive 10 to selectably access data stored on disk 22. A unique feature of PCB 15 is the provision of an opening of a shape corresponding to the shape of the well region 17 to allow PCB 15 to mount in close proximity adjacent the bottom portion of the base 12. This feature of the disk drive architecture allows for maximum efficiency in the arrangement of drive components to achieve a minimum total height when using both a PCB and a base plate in the drive design. Essentially, the total height of the disk and the spindle motor defines the total minimum height requirement for the drive. The integration of base 12, PCB 15 and motor 20 thereby functions to provide a drive having a reduced height.

Gasket 16 is of a unique structure in disk drives which allows an improved seal to be formed between base 12 and cover 14 to provide the controlled environment therebetween. Gasket 16 will be described with reference to Figs. 1 and 6. Fig. 6 is a partial, cross- sectional view of gasket 16 along line 6-6 of Fig. 1. As detailed in Fig. 6, the gasket cross section comprises walls 1 and 2, and rib 3 in opposed relation to the walls 1 and 2. Walls 1 and 2 form groove 5, sufficient to receive cover 14 and provide a seal when cover 14 is slidably mounted in groove 5. Gasket 16 also includes slats 7 having bores 18a formed therein corresponding to bores 18 in cover plate 14 for allowing the socket head cap screws (not shown) to engage thread mounting holes 19. A trough 11 is formed in base 12 and has substantially the same shape as cover 14 and gasket

16. Rib 3 conforms to a shape substantially the same as trough 11 and rib 3 engages trough 11 in a tongue-in- groove fashion. Gasket 16 is formed of a pliable material , preferably 40 Durometer polyurethane, such that when gasket 16 is sandwiched between cover 14 and base 12, an improved seal is formed between the cover 14 and base 12 to provide a controlled environment for operation of the disk drive. The assembled base 12, cover 14, and gasket 16 provide a controlled environment which is sealed to 1 atm, corresponding to 40,000 feet above and 1,000 feet below sea level. A filter 24 is provided to assist in ensuring a contaminant-free, controlled environment between base 12 and cover 14.

Filter 24 is slidably mounted in post 24A and notch 24B formed on the interior of cover 14.

The rigid structure of base 12, cover 14, and the mounting of components therein ensure that the actuator assembly 50 positions reading and writing heads 60 about the disk drive 10 in an accurate manner over a variety of operating conditions .

Fig. 2 is a top-level diagram showing the layout of the components in the disk drive 10. Fig. 2 serves to further illustrate the novel architecture of disk drive 10 of the instant invention. Specifically, disk 22 is shown rotatably mounted about axis 21 located at the center of disk 22. Axis 21 is located at a distance of approximately 3.15 inches from end side rail A and approximately 1.698 inches from side rail C of base 12. Disk clamp member 23 secures the disk 22 in place on spindle motor 20.

The positioning and operation of actuator assembly 50 is shown in Figs. 2 and 4. The actuator assembly 50 is mounted in recess 13 of base 12 to minimize the height required in the drive architecture. As is discussed in further detail below, actuator assembly 50 positions transducer means 60a and 60b, mounted on actuator arm assembly 52 (comprising actuator arms 52a and 52b) and support flexures 54a and 54b, to ensure that heads 60a and 60b, one of which is associated with each surface of disk 22, are positioned over individual data tracks lying in the same vertically oriented, cylindrical segment defining the same track on both surfaces of disk 22.

Spin motor flex circuit 30 is coupled to the header assembly 25 for providing control signals from the PCB 15 to the spindle motor 20 to rotate the disk 22 in response to control signals from PCB 15. Actuator flex circuit 32 carries electrical signals from header 25 to heads 60a and 60b and actuator assembly 50. Actuator flex circuit 32 is separated into three portions. A first portion carries current to the actuator coil 70. A second portion is a ground plane which separates the first, current-carrying portion from a third, data- carrying portion. The data-carrying portion provides signals to heads 60a and 60b for recording information on disk 22 and carries signals from heads 60a and 60b to the PCB 15 via header assembly 25 when reading data from disk 22. Actuator flex circuit 32 is electrically connected to pins 28 of header assembly 25. One portion of the actuator flex circuit 32 terminates at a point where the actuator flex circuit 32 joins actuator arm assembly 52. However, the second and third portions of the flexure 32 wrap around the shoulder of the actuator arm assembly 52 which surrounds the bearing cartridge 40. Wrapping the second and third portions of the actuator flex circuit 32 around the shoulder of the actuator arm assembly 52 provides access to current-carrying wires on one side of the flex circuit. Additionally, the radius of the curve defined by the actuator flex circuit 32 defines a torque which is exerted by the actuator flex circuit 32 on the actuator arm assembly 52. It is desirable to minimize the effect the torque exerted by the reverse flex circuit 32 on the actuator arm assembly to thus maximize the force exerted by the voice coil motor. With reference to Figs. 2 and 6, the structure and operation of the actuator assembly 50 will be hereinafter described. Actuator assembly 50 includes actuator arm assembly 52, flexures 54a and 54b, and read/write heads 60a and 60b. Actuator arm assembly 52 also includes first and second support arms 52a and 52b which support flexures 54a and 54b on which read/write heads 60a and 60b are mounted. Heads 60a and 60b preferably comprise thin-film transducers having a gap width of approximately 9.0 microns. In the preferred embodiment of the invention, flexures 54a and 54b are mounted to first and second support arms 52a and 52b, respectively, by means of a stamped metal post for interlocking each flexure 54a, 54b with support arms 52a and 52b, respectively. Actuator arm assembly 52 is mounted on actuator support pin 65 by bearing cartridge 40 and is secured by socket head cap screw 45, as is discussed more fully below with respect to Fig. 3B.

With reference to Figs. 2, 3, and 5, the force necessary to pivot actuator arm assembly 52, flexures 54a, 54b, and read/write heads 60, to position read/write heads 60 at specific tracks is generated by a voice coil motor including coil 70 and actuator magnet 66 mounted on an actuator assembly top support plate 55. Top support plate 55 and bottom support plate 53 are formed of a magnetically permeable material to provide returns for the magnetic field generated by magnet 66. Magnet 66 and actuator coil 70 are arranged so that coil 70 is placed in the magnetic field created by magnet 66. Actuator magnet 66 is preferably a single piece, bipolar magnet, preferably comprised of neodymium iron boron. Magnet 66 includes regions 66a and 66b for providing first and second magnetic fields B, and B₂ between respective poles in each region 66a and 66b, and bottom plate 53. The magnetic fields are encompassed in a closed magnetic circuit including various portions of the top plate 55, bottom plate 53, and support member 62. By containing the magnetic fields in the returns provided by the support member 62, and top and bottom plates 55 and 53, the magnetic field intensity of each field is increased in the region between the respective poles of the magnet and the bottom plate 53. The strength of the magnetic field in this region is directly related to the torque which the voice coil exerts on the actuator arm assembly 52, and thus the rotational (angular) velocity of the actuator arm assembly 52 and the seek times for the drive. Placing coil 70 between subarms 56a and 56b reduces the gap between magnet 66 and bottom plate 53, thereby decreasing flux leakage and increasing the strength of the respective magnetic fields. Thus, currents passing in opposite directions in coil 70 create torques in opposite directions to magnetic fields B, and B₂ so that actuator arm assembly 52 and the components mounted thereon may be pivoted to position heads at selected locations between inside and outside diameters of the data region on the disk 22.

It is important that there are no air gaps between support member 62 and either the top or bottom plates 55 or 53; any air gap would create a discontinuity in the return, greatly reducing the strength of the magnetic field. It should also be noted that a bend is provided in the top plate 55 forming an arm 55a. Arm 55a eliminates the need for the use of a second support member, thus reducing hot spots in the magnetic circuit. In operation, control signals are provided to the coil 70 via reverse flex circuit 32 (Fig. 2) to selectively control the actuator assembly 50 to position heads 60 at specific individual data tracks on disk 22. In the preferred embodiment of the invention, disk 22 comprises a two-sided platter having a total of 1805 tracks, yielding an unformatted storage capacity of approximately 112.3 Mbytes and a formatted capacity of 85 Mbytes. A plated, 1300 Oe disk for use in the disk drive of the present invention is currently available from Mitsui Comtek, Inc., a subsidiary of Mitsui & Co pany, U.S.A., Inc., 12980 Saratoga Avenue, Saratoga, California 95070-4666.

Tables 1 and 2 below specify certain characteristics of disk 22.

Table 1

Number Data Cylinders Sectors per Track = Number of Disks Number of Data Surfaces Bytes per Sector Data Bytes per Sector Total Data Capacity formatted)

Disk Diameter

Data Track Band Width

Track Density Bit Density (max)

Head Width Track Width Outermost Track Radius Innermost Track Radius

Also provided in actuator assembly 50 is a latch mechanism for securing the actuator arm assembly 52 in response to signals from the PCB 15 directing a "parking" of the drive, typically used whenever power is off and during transportation of the disk drive. The latch means comprises a second latch arm 58 mounted perpendicular with respect to the longitudinal axis of first and second actuator support arms 52a and 52b. Latch arm 58 has mounted thereon a magnetic capture element 57 which secures the actuator arm assembly 52 in a position where the read/write heads 60a and 60b are over a landing zone corresponding to a position at the innermost diameter of disk 22. Bumper 64 has a recess 64a for embedding magnet 68 therein. Bumper 64 and magnet 68, when assembled, are mounted in cavity 62b formed in column 62a of support member 62. In operation, when control signals are provided from PCB 15 to park the disk drive heads, actuator assembly 50 is driven in the manner described above to position heads 60a and 60b at the innermost diameter of the disk 22. As actuator assembly 50 rotates heads 60a and 60b, capture member 57 pivots via arm 58 into a slot (not shown) provided in column 62a. The magnetic forces generated by magnet 68 are such that capture member 57 is drawn into engagement with bumper 64 and thereby secures the position of the actuator arm assembly 52 at the innermost diameter location of the disk 22.

Actuator assembly 50 provides average data seek times of less than about 19 milliseconds, due to the high power-to-mass ratio of the voice coil motor and arm assembly 52, and the small moment of inertia of actuator arm assembly 52. The latch mechanism described above serves as the inside diameter crash stop for the actuator arm assembly

52; preferably, this inner crash stop is defined at a track radius of 0.88 inch. Also shown in Fig. 2 is a support post 34 serving as an outside diameter crash stop positioned between cover 14 and base 12. The outside diameter crash stop 34 inhibits movement of the actuator arm assembly 52 past an outer-most diameter of the drive, preferably at a track radius of about 1.83 inches.

Fig. 3A is a sectional view along line 3-3 in Fig.

2 of the hard disk drive of the present invention. Fig.

3 details the assembly of spin motor 20, a rotating shaft motor, in which a stator assembly 38 including stator lamination 39 is mounted in the recess 17 of base 12. First and second bearings 36 and 37 rotat.ably mount shaft 33 in the stator assembly 38. The use of a rotating shaft motor reduces the friction attributable to bearings 36 and 37, since rotation of the inner race (not shown) of each bearing 36 and 37 as opposed to the outer race (not shown) causes fewer rotations of the ball bearings between the inner the outer races. A hub 35 on shaft 33 supports disk 22 and rotor 41. The rotor 41 may comprise a multi-pole ring magnet. Spin motor 20 induces a disk rotation speed of approximately 2,892 rp in response to control signals provided by PCB 15 via flex cable 30. Rotational control signals, as discussed above, are generated by PCB 15 in conjunction with positioning signals for actuator assembly 50 to enable specific data retrieval. Fig. 3 also shows the relationship of the read/write heads 60a and 60b to the disk 22. Heads 60a and 60b are supported by actuator assembly 50 which allows the heads 60a and 60b to "fly" over the surfaces of the disk 22 on the air float created by rotation of the disk 22. Flexures 54a and 54b provide a gimballing action which allows heads 60a and 60b to fly flat, thereby orienting the surface of each head 60a and 60b facing disk 22 so that it is parallel to the surface of disk 22 while disk 22 is rotating and each flexure 54a or 54b is under load. In the preferred embodiment, the heads 60 fly at a height of approximately 6.0 microinches over the disk. Each head 60 represents a load of approximately 5 grams on each flexure 54.

Fig. 3B details the bearing assembly 40 of the actuator assembly 50. Fig. 3B is an exploded view of the actuator mounting assembly shown in Fig. 3A. Fig. 3B specifically shows bearing assembly 40 mounted on actuator sleeve 42 abutting bottom plate 53. Actuator sleeve 42 is- secured to bottom plate 53 of actuator assembly 50 and base 12 by means of an actuator support pin 65 threaded to receive hex nut 45. Actuator arm assembly 52 is mounted to an outer sleeve 48 containing actuator bearing cartridges 47a and 47b housing actuator bearings 46. Cartridges 47a and 47b are separated by a spacer 44. Housing 48, shaft 33, and spacer 44 may be manufactured from, for example, stainless steel. Actuator bearing assembly 40 provides a maximum torque of 1.3 grams per centimeter as measured on the inner shaft with the outer housing rotating at 200 rpm thereby aiding in the reduction of data seek times. The many features and advantages of the disk drive of the present invention will be apparent to those skilled in the art from the description of the preferred embodiments and the drawings. The disk drive described herein provides a high-speed, low-power, compact disk drive suitable for use in portable computers. The drive utilizes an average of 2.5 watts during seek functions and 3.5 watts when reading or writing information, and has a data average access time less than about 19 ms . Numerous variations are possible as will be apparent to those skilled in the art; such variations are intended to be within the scope of the invention as defined by this specification and the following claims are intended to cover all the modifications and equivalents falling within the scope of the invention.

Claims

CLAIMS What is claimed is:

1. A low height disk drive, comprising: a base having a top and a bottom, storage means, supported on said top of said base, for storing data, interactive means for reading information from and writing information on said storage means, and actuator means, supported on said base and responsive to control signals, for selectively positioning said interactive means with respect to said storage means, and a cover sealably attached to said base to enclose said storage means, said interactive means, and said actuator means; and control means, mounted adjacent to said bottom of said base, for generating control signals to control said actuator means and for providing information signals to and receiving information signals from said interactive means, said base, storage means, interactive means, actuator means, cover, and control means having an overall maximum assembled height of approximately three-quarters of an inch (0.75").

2. The low height disk drive according to Claim 1 wherein said base and said cover have a length of 5.15 inches (5.15") and a width of four inches (4"). 3. The disk drive as claimed in Claim 2 wherein said storage means is mounted on a spindle motor for selectively rotating said storage means responsive to said control signals, said base includes a well region having substantially the same shape as said spindle motor for mounting said spindle motor, and said control means comprises a printed circuit board having an opening having a shape corresponding to the shape of said well region and said printed circuit board is mounted to said bottom of said base.

4. The low height disk drive of claim 3 wherein said actuator is pivotably mounted about a pivot point, said storage means is pivotably mounted about an axis located at the center of said storage means, and the distance between said pivot point and said rotational axis is about two and two-tenths (2.2) inches.

5. A low height disk drive, comprising: a base having a top and a bottom, storage means, supported on said top of said base, for storing data, interactive means for reading information from and writing information on said storage means, and actuator means, supported on said base and responsive to control signals, for selectively positioning said interactive means with respect to said storage means, and a cover sealably attached to said base to enclose said storage means, said interactive means, and said actuator means; and control means, mounted adjacent to said bottom of said base, for generating control signals to control said actuator means and for providing information signals to and receiving information signals from said interactive means, said base, interactive means, actuator means, cover, and control means having an overall maximum assembled height of approximately eight- tenths of an inch (0.8").

6. A low height disk drive according to claim 5 wherein said base has a length of 5.15 inches and width of 4.00 inches and said cover has approximately the same dimensions as said base.

7. A low height disk drive according to claim 6 wherein said actuator means comprises a first actuator arm having first and second ends, pivotably mounted about an actuator pivot point on said base plate, and said storage means is rotatably mounted about an axis positioned at the center of said storage means, said actuator pivot point being positioned at a predetermined distance of less than about 2.5 inches from said rotational axis. 8. The disk drive as claimed in Claim 7 wherein said predetermined distance is about 2.20 inches from said central point.

9. The disk drive as claimed in Claim 8 wherein said storage means is characterized as having a plurality of concentric tracks formed thereon, and wherein the skew angle between said transducer means and a line normal to each of said concentric tracks is in a range of (-)7.5" - (+)17.2^*.

10. The disk drive as claimed in Claim 5 wherein said control means comprises a printed circuit board mounted abutting said base and wherein the height of said printed circuit board, said cover and said base, when assembled, is 0.75 inch.

11. The disk drive as claimed in Claim 10 wherein said storage means is mounted on a spindle motor for selectively rotating said storage means responsive to said control signals, said base includes a well region having substantially the same shape as said spindle motor for mounting said spindle motor, and said printed circuit board includes an opening having a shape corresponding to the shape of said well region and said printed circuit board is mounted to said bottom of said base. 12. The disk drive as claimed in Claim 11 further including a gasket provided between said base and said cover for providing a seal therebetween when said base and cover are engaged, wherein said base includes a trench characterized as having a shape substantially the 'same as said cover, wherein said gasket is characterized as having a shape substantially the same as said cover and a rectangular cross section, said gasket further having a channel formed therein, said channel characterized as having a shape substantially the same as said cover for slidably receiving said cover plate, and a rib being of the same shape as said trench and in an opposed relation to said channel with reference to said rectangular cross section, said rib for engaging said trench in a tongue-in-groove fashion.

13. The disk drive as claimed in Claim 11 wherein said cover, gasket and base maintain said length, width, and height under operating conditions in the temperature range of 5^*C - 55'C.

14. The disk drive as claimed in Claim 5 wherein said base of said disk drive has a first end and a second end, and said actuator pivot point is positioned about 1.12 inches from said first end.

15. The disk drive as claimed in Claim 5 wherein said base of said drive has a first side and a second side, and said actuator pivot point is positioned about 2.79 inches from said first side.

16. The disk drive as claimed in Claim 5 wherein said storage means comprises a single disk having at least 1800 tracks for providing a formatted storage capacity of at least 80 MBytes.

17. The disk drive as claimed in Claim 16 wherein the weight of the drive is less than one pound.

18. The disk drive as claimed in Claim 5 wherein said actuator means is cast of magnesium.

19. The disk drive as claimed in Claim 5 wherein said actuator means further includes a second actuator arm mounted between said first and second ends of said first actuator arm in a perpendicular relationship thereto, said first and second actuator arms defining a plane substantially parallel to the plane defined by said storage means.

20. The disk drive of Claim 5 wherein said actuator further comprises magnetic means, mounted parallel to said base plate, for providing a magnetic field, and a coil, supported by said second end of said first actuator arm and lying in a plane substantially parallel to said disk, for passing a current in the direction of said magnetic field. 21. The disk drive as claimed in Claim 20 wherein said actuator means further includes latch means, comprising magnetically permeable capture member mounted on said second actuator arm, and magnetic parking means for capturing and magnetically retaining said capture member comprising a magnet for providing a magnetic field and magnetic field containing member having an air gap substantially parallel to the magnetic flux lines produced in said magnetic field.

22. The disk drive as claimed in Claim 21 wherein said drive further includes means for electrically interconnecting said control means, transducer means, and actuator means comprising a header for providing electrical interconnections between said control means and the controlled environment between said cover and said base plate, and a flex circuit having first, second, and third portions, said first portion for electrically interconnecting said header and said transducer means, and said second portion for electrically interconnecting said header and said coil, and said third portion comprising a ground plane separating said first and second portions of said reverse flex circuit. 23. The disk drive as claimed in Claim 5 wherein said means provided on said base for rotating said storage means about said rotational axis in response to said control signals comprises a spindle motor.

24. A hard disk drive, comprising: a base having a length of 5.15 inches and a width of 4.00 inches, and first and second surfaces; a printed circuit board (PCB), mounted on said first surface of said base, for providing control signals; a cover plate having said length and said width and engaged with said base to provide a controlled environment between said base and said cover; a gasket interposed between said cover and said base for securing a seal therebetween; storage means comprising at least one disk rotatably mounted at a first point on said base plate, said disk having a plurality of concentric tracks and a diameter of approximately 3.74 inches; means for rotating said storage means in response to said control signals; transducer means for reading information from and writing information on said storage means; actuator means pivotably mounted at a second pivot point on said base plate, said second pivot point being spaced a distance of less than 2.5 inches from said first pivot point, said actuator means for positioning said transducer means in a plane substantially parallel to the plane defined by said storage means; magnet structure including a magnetic means for providing magnetic field and coil means mounted on said actuator arm and lying in a plane substantially parallel to said disk, for passing a current in the direction of said magnetic field; means for coupling said printed circuit board control signals to said actuator means and said means for rotating said storage means; and parking means for magnetically interacting with said actuator means to park said transducer means at a predetermined location on said storage means.

25. The disk drive as claimed in Claim 24 wherein said height of said PCB, said cover and said base when assembled with said gasket interposed between said base and cover is 0.75 inch.

26. The hard disk drive as claimed in Claim 25 wherein said means for rotating said disk comprises a spindle motor, said base includes a well region having substantially the same shape as said spindle motor for receiving said spindle motor, and said PCB includes an opening having a shape corresponding to the shape of said well region and said PCB is mounted abutting said first surface of said base.

27. The disk drive as claimed in Claim 25 wherein said base plate includes a trench characterized as having a shape substantially the same as said cover, wherein said gasket is characterized as having a shape substantially the same as said cover and a rectangular cross section, said gasket further having a channel formed therein, said channel characterized as having a shape substantially the same as said cover for slidably receiving said cover plate, and a rib being of the same shape as said trench and in an opposed relation to said channel with reference to said rectangular cross section, said rib for interconnecting with said trench in a tongue-in-groove fashion.

28. The disk drive as claimed in Claim 25 wherein said second pivot point is about 2.20 inches from said first point.

29. The disk drive as claimed in Claim 25 wherein said base of said disk drive has a first end and a second end, and wherein said second pivot point is about 1.10 inches from said first end.

30. The disk drive as claimed in Claim 24 wherein said base of said drive is defined by a first side and a second side, and wherein said second pivot point is about 2.8 inches from said first side.

31. The disk drive as claimed in Claim 24 wherein said at least one disk has a storage capacity of 85 MBytes.

32. The disk drive as claimed in Claim 31 wherein the weight of the drive is less than one pound.

33. The disk drive as claimed in Claim 24 wherein said actuator means includes a first actuator arm having first and second ends pivotably mounted about an actuator pivot point.

34. The disk drive as claimed in Claim 33 wherein said actuator means further includes a second actuator arm mounted between said first and second end of said fist actuator arm in a perpendicular relationship thereto, said first and second actuator arms .defining a plane substantially parallel to the plane defined by said storage means .

35. The disk drive as claimed in Claim 34 wherein said actuator means further includes latch means, comprising magnetically permeable capture member mounted on said second actuator arm, and magnetic parking means for capturing and magnetically retaining said capture member comprising a magnet for providing a magnetic field and magnetic field containing member having an air gap substantially parallel to the magnetic flux lines produced in said magnetic field.

36. A hard disk drive architecture, comprising: a base and a cover for defining a controlled environment, said base and said cover being engaged with a gasket therebetween, said base and cover further having a length of 5.15 inches, a width of 4.00 inches, and a height of 0.75 inch; storage means comprising at least one disk rotatably mounted about an axis passing through the center of said disk, said disk having a plurality of concentric tracks and a diameter of approximately 3.74 inches; spindle motor for rotating said storage means in response to said control signals; transducer means for reading information from and writing information on said storage means; actuator means pivotably mounted about an actuator pivot point on said base plate, said actuator means for positioning said transducer means in a plane substantially parallel to the plane defined by said storage means, said actuator pivot point being about 2.2 inches from said rotational axis; magnet structure including a magnetic means for providing magnetic field and coil means mounted on said actuator arm and lying in a plane substantially parallel to said disk, for passing a current in the direction of said magnetic field; means for coupling said printed circuit board control signals to said actuator means and said means for rotating said storage means; and parking means for magnetically interacting with said actuator means to park said transducer means at a predetermined location on said storage means.

37. A disk drive, comprising: a base having a length of 5.15 inches and width of 4.00 inches; a cover having approximately the same dimensions as said base and engaging said base to provide a controlled environment between said base and said cover; storage means rotatably mounted on said base, said storage means having a center and a plurality of concentric tracks; control means for providing control signals; means provided on said base for rotating said storage means about an axis passing through said center of said storage means in response to said control signals; transducer means for reading information from and writing information to said storage means; and actuator means, responsive to said control signals, for positioning said transducer means over selected ones of said concentric tracks, comprising a first actuator arm having first and second ends, pivotably mounted about an actuator pivot point on said base plate, said actuator pivot point being positioned at a predetermined distance of less than about 2.5 inches from said rotational axis.

38. A low height disk drive, comprising: a housing defining the maximum height, length and width of said disk drive, said housing having a maximum height of approximately three-quarters of an inch (0.75"); a base having a top and a bottom, storage means, supported on said top of said base, for storing data, interactive means for reading information from and writing information on said storage means, and actuator means, supported on said top of said base and responsive to control signals, for selectively positioning said interactive means with respect to said storage means, and a cover sealably attached to said top of said base to enclose said storage means, said interactive means, and said actuator means; and control means for generating control signals to control said actuator means and for providing information signals to and receiving information signals from said interactive means.

39. A low height disk drive according to claim 38, wherein: said storage means comprises a disk defining a plane; and said housing has a height no greater than three- quarters of an inch (0.75") in the direction perpendicular to said plane of said disk.

40. A low height disk drive according to claim 39, therein said housing has a length of approximately five and fifteen hundredths of an inch (5.15") and a width of approximately four inches (4").

41. A low height disk drive, comprising: a housing having a bottom, said housing defining the maximum length and width of said disk drive; a disk having a plurality of tracks for storing data; a spin motor for mounting said disk in said housing and for rotating said disk; at least one transducer for interacting with said disk to read data from and record data on said tracks; actuator means for supporting said transducer adjacent to said disk; and a printed circuit board including circuitry for controlling said actuator means to position said transducer over a selected one of said tracks and for controlling said spin motor, said printed circuit board being mounted on said housing so that said printed circuit board is adjacent to said bottom of said housing and so that said housing and said printed circuit board have an overall, maximum height of approximately three- quarters of an inch (0.75").

42. A low height disk drive according to claim 41, wherein: said means for mounting said disk and for rotating said disk comprises a motor; said housing has a mounting surface having a recessed portion; and said motor is mounted in said recessed portion of said housing.

43. A disk drive responsive to a host computer and having an overall height of three-quarters of an inch (0.75") or less, comprising: a base plate, said base plate having a top, a bottom, and first and second side rails extending from the bottom of said base plate; a disk rotatably supported on the top of said base plate; interactive means for reading information from and writing information on said disk; actuator means, supported at the first end of said top of said base plate and responsive to control signals, for selectively positioning said interactive means with respect to said disk; a header provided in said base and having pins extending perpendicular to the bottom of said base plate, said pins being electrically interconnected with said interactive means; control means, confined between said first and second side rails, for generating control signals, and for providing information signals to and receiving information signals from said interactive means via said header, said control means comprising a connector for receiving said pins; and a cover sealably attached to said top of said base plate to provide a controlled environment between said cover and said base plate for said disk, said interactive means, and said actuator means, said base plate and said cover having an overall, maximum height, of approximately three-quarters of an inch (0.75").