US20010028536A1 - Head assembly and disk drive - Google Patents
Head assembly and disk drive Download PDFInfo
- Publication number
- US20010028536A1 US20010028536A1 US09/358,334 US35833499A US2001028536A1 US 20010028536 A1 US20010028536 A1 US 20010028536A1 US 35833499 A US35833499 A US 35833499A US 2001028536 A1 US2001028536 A1 US 2001028536A1
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- United States
- Prior art keywords
- slider
- head slider
- head
- suspension
- gimbal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B5/60—Fluid-dynamic spacing of heads from record-carriers
- G11B5/6005—Specially adapted for spacing from a rotating disc using a fluid cushion
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B21/00—Head arrangements not specific to the method of recording or reproducing
- G11B21/16—Supporting the heads; Supporting the sockets for plug-in heads
- G11B21/20—Supporting the heads; Supporting the sockets for plug-in heads while the head is in operative position but stationary or permitting minor movements to follow irregularities in surface of record carrier
- G11B21/21—Supporting the heads; Supporting the sockets for plug-in heads while the head is in operative position but stationary or permitting minor movements to follow irregularities in surface of record carrier with provision for maintaining desired spacing of head from record carrier, e.g. fluid-dynamic spacing, slider
Definitions
- the present invention relates generally to a magnetic head assembly including a magnetic head slider having a plurality of pads, and more particularly to a magnetic head assembly capable of preventing stiction of a magnetic head slider to a magnetic disk during the start of rotation of the magnetic disk drive.
- flying type magnetic head sliders employing the contact start and stop (CSS) system are frequently used.
- the magnetic head slider comes into contact with the magnetic disk when the disk drive stops rotating, but whereas during rotation, the magnetic head slider is kept flying at a microscopic height from the disk surface by an air flow generated over the surface of the magnetic disk, which rotates at a high speed during the recording or reproduction of information.
- an electromagnetic transducer i.e., a magnetic head element
- a magnetic head element To maintain the slider in position, it is supported by a suspension. Accordingly, when the magnetic disk is not being rotated, the slider (including the electromagnetic transducer) is in contact with the disk surface, whereas when the magnetic disk is rotated, an air bearing surface of the slider that is opposed to the magnetic disk receives an air flow generated by the rotation of the magnetic disk, and the slider flies a small distance either above or below the disk surface.
- the electromagnetic transducer built into the slider is moved over the disk surface while being supported by the suspension, and performs recording or reproduction of information on a given track.
- a pair of rails are generally provided along opposite side portions of the surface of the magnetic head slider that opposes the disk surface.
- Each of these two rails includes a flat air bearing surface.
- a tapering surface is formed on each rail at its air inlet end portion. The air bearing surface of each rail receives an air flow generated by the high-speed rotation of the magnetic disk, which makes the slider fly above (or below) the disk, maintaining a microscopic distance between the disk surface and the electromagnetic transducer.
- the surface roughness of the magnetic disk has conventionally been increased to a suitable level.
- increases in surface roughness have the drawback of causing an increase in the flying height.
- the surface roughness of the magnetic disk needs to be decreased, even though such a decrease in roughness increases stiction in conventional devices.
- a protective film made of a hard material such as carbon, and a lubricating layer for reducing friction and wear of the protective film are formed on a recording layer of the disk. Due to the presence of the lubricating layer, friction and wear of the protective film can be reduced.
- a protective film made of a hard material such as carbon and a lubricating layer for reducing friction and wear of the protective film are formed on a recording layer of the disk. Due to the presence of the lubricating layer, friction and wear of the protective film can be reduced.
- stiction between the disk and the slider may occur, preventing the disk drive from being restarted.
- a three-phase Hall-less motor employing no Hall element is generally used as the motor for rotating the spindle.
- a CSS type magnetic disk drive the magnetic head slider comes into contact with the magnetic disk when the disk drive is powered off, as mentioned above.
- a current is passed through any one of the three-phase coils to position the coil near a permanent magnet.
- the motor is rotated in either the forward direction or the reverse direction, depending upon the positional relationship between the coil and the permanent magnet upon stopping of the disk drive, so that the motor is rotated forwardly or reversely by about 60° to position the coil near the permanent magnet.
- the current passing through each phase is controlled to be switched, thereby continuously rotating the motor in the forward direction.
- the rotating direction of the motor is determined according to the positional relationship between the coil and the permanent magnet upon stopping of the disk drive. Accordingly, the initial reverse rotation of the motor occurs with a probability of about 50%.
- FIG. 1 is a schematic side view of a magnetic head slider 2 parked on a magnetic disk 4 .
- an arrow R. denotes the forward rotating direction of the magnetic disk 4
- an arrow R. denotes the reverse rotating direction of the magnetic disk 4 .
- Two pads 6 are formed on the air bearing surfaces of the head slider 2 near the air inlet end of the head slider 2 , although only one pad 6 is shown in the FIG. 1 view.
- two pads 8 are formed on the air bearing surfaces of the head slider 2 at an intermediate position between the air inlet end and the air outlet end of the head slider 2 , although only one is shown in FIG. 1.
- the pad 8 that is formed on the air bearing surface where a head element (transducer) is formed is located at a substantially longitudinally central position of the head slider 2 . The reason for locating the pad 8 in such a position is to minimize the spacing between the head element and the magnetic disk 4 during flying of the magnetic head slider 2 , thereby reducing wasted space and preventing projection of the pad 8 beyond the minimum flying height of the magnetic head slider 2 .
- Reference numeral 10 denotes the center of gravity of the slider 2 , about which moments are generated when the spindle is rotated.
- a clockwise moment M 1 (as viewed in FIG. 1) is generated.
- This clockwise moment M 1 causes the pads 6 to be pressed against the magnetic disk 4 .
- the overhang of the slider 2 that projects between the pads 6 and the lower edge of the air inlet end of the slider 2 is small, so that there is little possibility that this lower edge of the air inlet end of the slider 2 will come into contact with the recording surface of the magnetic disk 4 .
- slider 2 is rotated in direction M 1 , there is little chance that its lower right hand comer (as shown in FIG. 1) will contact the disk 4 .
- the lower edge of slider 2 being referred to is that shown at the lower left-hand corner, as shown in FIG. 1.
- Such contact between the lower edge of the slider 2 and the magnetic disk 4 may hinder the ability of the spindle to smoothly start rotating the disk 4 .
- the present invention provides an improved head assembly in which contact between the slider edges and the disk medium is eliminated, or at least minimized, even during reverse rotation, by changing the location of where the spring load is applied to the slider. If the spring load is moved from the center of gravity of the slider to a position between the center of gravity of the slider and the air inlet end of the slider, a moment is created that reduces the effects of the counterclockwise moment M 2 (see FIG. 1), whereby counterclockwise rotation of the slider that may occur when the disk medium is rotated in the reverse direction is reduced or eliminated. Accordingly, with the present invention, the probability of contact between the outer edge of the slider and the disk is reduced.
- the present invention relates to a head assembly (or a disk drive with such a head assembly) that includes a suspension having a roundedly bent portion for generating a spring load with a gimbal located on that suspension, and where the suspension has a slider mounting portion thereon. Additionally, there is a head slider mounted on the slider mounting portion of said gimbal, and the head slider includes an air bearing surface, an air inlet end, and an air outlet end.
- the spring load of the suspension is applied to the head slider at a load point that is offset from a center of gravity of the head slider, such that the offset load point is located between the center of gravity of the head slider and the air inlet end of said head slider.
- the head slider also includes several pads extending from its air bearing surface, and the offset load point of the spring load of the suspension is preferably set to substantially coincide with a center of gravity of the plurality of pads.
- the offset load point may be set to substantially coincide with a position lying on a straight line connecting two of the pads formed near the air inlet end.
- the first configuration includes a reinforcing plate connected to the suspension, and a pivot formed on the reinforcing plate and kept in pressure contact with the slider mounting portion of the gimbal, such that the pivot applies the spring load of the suspension to the head slider.
- the gimbal is bent at a neck portion thereof by a given angle with respect to the suspension such that the spring load of the suspension is applied to the head slider at the offset load point.
- FIG. 1 is a side view of a magnetic head slider, for illustrating a problem in the prior art
- FIG. 2 is a perspective view of a magnetic disk drive of the present invention with its cover removed;
- FIG. 3A is a perspective view of a head assembly according to a first preferred embodiment of the present invention.
- FIG. 3B is a longitudinal sectional view of the head assembly shown in FIG. 3A;
- FIG. 4 is a plan view of a head slider of the head assembly shown in FIG. 3A;
- FIG. 5A is a side view of the head slider in its flying condition, showing its pitch angle
- FIG. 5B is an end view of the head slider in its flying condition, showing its roll angle
- FIG. 6 is a sectional view of an essential part of an MR head mounted on the head slider
- FIG. 7A is a top plan view of the head assembly according to the first preferred embodiment of the present invention, showing details not visible in FIGS. 3A and 3B;
- FIG. 7B is a side view of the head assembly shown in FIG. 7A;
- FIG. 8 is a bottom plan view of the head assembly shown in FIG. 7A;
- FIG. 9A is a top plan view of a head assembly according to a second preferred embodiment of the present invention.
- FIG. 9B is a side view of the head assembly shown in FIG. 9A;
- FIG. 10 is a side view of the head assembly according to the second preferred embodiment showing the spring portion with rounded bend therein.
- FIG. 2 there is shown a perspective view of a magnetic disk drive with its cover removed.
- Reference numeral 12 denotes a base.
- a shaft 14 is fixed to the base 12 .
- a spindle hub (not shown) is rotatably mounted on the shaft 14 so as to be driven by a Hall-less spindle motor (not shown).
- a plurality of magnetic disks 16 and spacers are mounted on the spindle hub in such a manner as to be alternately stacked. That is, the plural magnetic disks 16 are fixedly mounted on the spindle hub by securing a disk clamp 18 to the spindle hub by a plurality of screws 20 , and these disks 16 are equally spaced apart at a given distance by the spacers.
- Reference numeral 22 denotes a rotary actuator consisting of an actuator arm assembly 24 and a magnetic circuit 26 .
- the actuator arm assembly 24 is mounted so as to be rotatable about a shaft 28 , which is fixed to the base 12 .
- the actuator arm assembly 24 includes an actuator block 30 that is rotatably mounted on the shaft 28 through a pair of bearings.
- the actuator arm assembly 24 further includes a plurality of actuator arms 32 that extend from the actuator block 30 in one direction, and a head assembly 34 that is fixed to a front end portion of each actuator arm 32 .
- Each head assembly 34 includes a head slider 36 that has a head element (i.e., such as an electromagnetic transducer or an optical element) for reading/writing data from/to the corresponding magnetic disk 16 , and a suspension 38 that has a front end portion for supporting the head slider 36 and a base end portion fixed to the corresponding actuator arm 32 .
- a coil (not shown) is supported on the actuator block 30 the opposite side from where the actuator arms 32 extend from.
- the magnetic circuit 26 and the coil, which is inserted into a gap in the magnetic circuit 26 constitute a voice coil motor (VCM) 40 .
- VCM voice coil motor
- Reference numeral 42 denotes a flexible printed circuit board (FPC) for supplying a write signal to the magnetic head element and for taking a read signal from the magnetic head element.
- the flexible printed circuit board 42 is fixed at one end to a side surface of the actuator block 30 .
- FIG. 3A is a perspective view of a head assembly 34 according to a first preferred embodiment of the present invention
- FIG. 3B is a longitudinal sectional view of the head assembly 34 shown in FIG. 3A.
- Reference numeral 38 denotes a suspension, which may be formed of stainless steel, for example.
- the suspension 38 includes a spring portion 38 a and a rigid portion 38 b .
- a reinforcing plate 44 is spot-welded to the lower surface of the rigid portion 38 b of the suspension 38 .
- the total length of the head assembly 34 is approximately 16.0 mm, and its maximum width is approximately 4.4 mm at its base end where a spacer 52 is affixed.
- the suspension 38 preferably has a thickness of approximately 22 ⁇ m and a weight of approximately 2.4 mg. Note that the preceding dimensions were given for the purposes of illustration only, and it is contemplated that alternate dimensions may also be utilized without departing from the spirit of the invention.
- the suspension 38 preferably includes an integrally formed gimbal 46 , located near its front end. This gimbal 46 is created by a substantially U-shaped slit 48 formed at the front end portion of the suspension 38 which thereby defines the gimbal 46 inside of the slit 48 .
- a magnetic head slider 36 is fixed to the upper surface of the gimbal 46 by an adhesive or the like.
- the spacer 52 (which is used for fixing the head assembly 34 to the corresponding actuator arm 34 ) is preferably fixed to the base end portion of the suspension 38 by spot welding.
- a pivot 50 is formed at a front end portion of the reinforcing plate 44 .
- the pivot 50 is in contact with the lower surface of the gimbal 46 to thereby support the magnetic head slider 36 .
- the reinforcing plate 44 preferably has a total length of approximately 5.0 mm, a maximum width of approximately 2.0 mm, a thickness of approximately 30 ⁇ m, and an approximate weight of 1.4 mg, although other dimensions and weights are also contemplated as being within the scope of the invention.
- the pivot 50 preferably has a height of approximately 50 ⁇ m
- the magnetic head slider 36 preferably has a length of approximately 1.2 mm, a width of approximately 1.0 mm, a height of approximately 0.3 mm, and a weight of approximately 1.6 mg.
- the gimbal 46 is slightly raised above the upper surface of the suspension 38 by the pivot 50 . Accordingly, a preload F is applied to the gimbal 46 when the head slider 36 is in an unloaded condition (i.e., when the slider is not loaded onto the magnetic disk). In this condition, the gimbal 46 is maintained substantially parallel with the suspension 38 .
- the spring portion 38 a of the suspension 38 is bent to form a generally rounded bend as shown in FIG. 10.
- the spring load of the spring portion 38 a is applied through the pivot 50 to the head slider 36 when the head assembly 34 is mounted in the magnetic disk drive. That is, the tip of the pivot 50 falls at a load point of the spring load.
- an MR wiring pattern 54 and a coil wiring pattern 60 are formed by printing upon the upper surface of the suspension 38 .
- the MR wiring pattern 54 consists of a pair of lead lines 56 and 58
- the coil wiring pattern 60 consists of a pair of lead lines 62 and 64 .
- Each of the lead lines 56 , 58 , 62 , and 64 is preferably formed mainly of copper, and preferably gold is deposited on the copper through nickel by evaporation.
- the lead lines 56 and 58 have first ends respectively connected to the terminals of a magnetoresistive element (MR element, which will hereinafter be described) in the magnetic head slider 36 by bonding through gold balls 66 .
- the lead lines 62 and 64 have first ends respectively connected to the terminals of a coil (which will hereinafter be described) in the magnetic head slider 36 by bonding through gold balls 68 .
- a tab 70 is formed at one side edge of the suspension 38 , and four terminals 72 , 74 , 76 , and 78 are formed on the tab 70 .
- the terminals 72 , 74 , 76 , and 78 are connected to the second ends of the lead lines 56 , 58 , 62 , and 64 , respectively.
- FIG. 4 there is shown a plan view of the magnetic head slider 36 used in the head assembly 34 .
- a pair of rails 80 and 82 is formed on the surface of the slider 36 that will oppose the surface of the magnetic disk.
- the rails 80 and 82 respectively have flat air bearing surfaces 80 a and 82 a for generating a flying force while the disk is rotating.
- Tapering surfaces 80 b and 82 b are formed at the air inlet end portions of the rails 80 and 82 , respectively.
- a groove 86 is defined between the rails 80 and 82 to expand the air previously compressed and thereby to generate a negative pressure.
- a head element 88 is formed on the air outlet end of the slider 36 at a transverse position adjacent to the rail 80 .
- a center rail 84 is formed between the rails 80 and 82 at a portion near the air inlet end of the slider 36 .
- Each of the rails 80 and 82 is shaped to have a wider width at its opposite end portions near the air inlet end and the air outlet end, and a narrower width at its longitudinally intermediate portion, thereby suppressing variations in flying height due to changes in the yaw angle. Further, the formation of the tapering surfaces 80 b and 82 b near the air inlet end of the slider 36 makes it possible to minimize variations in flying height when dust is present upon the magnetic disk.
- Two pads 90 and 92 are formed on the air bearing surface 80 a of the rail 80
- two pads 94 and 96 are formed on the air bearing surface 82 a of the rail 82 .
- the pads 90 , 92 , 94 , and 96 may be formed from diamond-like carbon (DLC), for example.
- the pads 90 and 94 are preferably formed near the air inlet end of the slider 36 at the same position with respect to the longitudinal axis of the slider 36 .
- Pad 90 extends across the boundary between the air bearing surface 80 a and the tapering surface 80 b .
- pad 94 extends across the boundary between the air bearing surface 82 a and the tapering surface 82 b.
- the pads 92 and 96 are preferably formed at different positions from each other along the longitudinal axis.
- the pads 92 and 96 are preferably located at different positions between the air inlet end and the air outlet end of the slider 36 at such positions where the pads 92 and 96 do not project beyond a minimum flying height (to be hereinafter described) during flying of the slider 36 .
- the pad 92 formed on the rail 80 is preferably shifted toward the air inlet end of the slider 36 in comparison with the pad 96 formed on the rail 82 .
- the positions of the pads 92 and 96 are not located at the same position along the longitudinal axis because the flying height of the rail 80 adjacent to the head element 88 is set to be lower than the flying height of the rail 82 .
- the flying height of the rail 80 can be made smaller than the flying height of the rail 82 by setting the width of the rail 80 to be less than the width of the rail 82 , as shown in FIG. 4.
- FIGS. 5A and 5B the flying attitude of the head slider 36 is shown.
- the head slider 36 is so designed as to have a pitch angle A shown in FIG. 5A and a roll angle B shown in FIG. 5B during its flying condition so that the head element 88 comes closest to the minimum flying height 98 shown by the dashed line.
- the positions and heights of the pads 90 , 92 , 94 , and 96 are set so that they do not project beyond the minimum flying height 98 during the flying condition of the slider 36 .
- the pitch angle A is defined as an angle between the longitudinal axis of the slider 36 and a line denoting the minimum flying height 98 during the flying condition of the slider 36 as shown in FIG. 5A
- the roll angle B is defined as an angle between a transverse line of the slider 36 and a line denoting the minimum flying height 98 during the flying condition of the slider 36 as shown in FIG. 5B.
- the pitch angle A is preferably between 50-200 microradians (and is more preferably between 90-150 microradians)
- the roll angle B is preferably between 10-80 microradians (and is more preferably between 20-40 microradians).
- reference symbol G 1 denotes the center of gravity of the head slider 36 .
- the head slider 36 is mounted on a suspension so that the load point of the spring load of the suspension coincides with the center of gravity G 1 of the head slider 36 .
- the pivot 50 is positioned relative to the head slider 36 when fixed to the gimbal 46 so that the load point of the spring portion 38 a of the suspension 38 is shifted from the center of gravity G 1 of the slider 36 toward the air inlet end of the slider 36 .
- the load point is set to coincide with a center of gravity G 2 of the pads 90 , 92 , 94 , and 96 (as opposed to point G 1 , which is the center of gravity of the entire slider 36 ). Accordingly, the spring load can be uniformly applied to the pads 90 to 96 , thereby preventing abnormal wearing of the pads 90 to 96 due to nonuniform contact of the pads 90 to 96 with the magnetic disk surface. Accordingly, it is possible to reduce the wear of each pad due to CSS and to obtain stable flying start characteristics.
- the load point may be set to coincide with an intersection F of a longitudinally extending center line of the slider 36 and a transverse line connecting the pads 90 and 94 formed near the air inlet end of the slider 36 .
- the load point is determined by the position of the pivot 50 relative to the slider 36 .
- the magnetic head slider 36 has a conductive substrate 100 and a nonmagnetic insulating layer 102 formed on the conductive substrate 100 .
- the nonmagnetic insulating layer 102 may be formed of alumina (Al 2 O 3 ), for example.
- First and second magnetic shields 104 and 106 which may be formed of nickel-iron (Ni—Fe), for example, are embedded in the nonmagnetic insulating layer 102 .
- a gap 108 for improving the reproductive resolution is defined between the first and second magnetic shields 104 and 106 on a front end surface (i.e., the medium opposing surface) 110 of the head slider 36 .
- a magnetoresistive element (MR element) 112 which may be formed of nickel-iron (Ni—Fe), is embedded in the gap 108 so as to be exposed to the front end surface 110 of the head slider 36 .
- a sense current source is connected to a pair of terminals of the magnetoresistive element 112 to supply a constant sense current to the magnetoresistive element 112 .
- Reference numeral 116 denotes a magnetic pole having one end exposed to the front end surface 110 of the head slider 36 and the other end connected to the second magnetic shield 106 .
- a conductor coil 114 is wound substantially around a connected portion between the magnetic pole 116 and the second magnetic shield 106 .
- the magnetoresistive element 112 In reading information recorded on the magnetic disk 16 , the magnetoresistive element 112 is used. That is, a signal magnetic flux from a recording track of the magnetic disk 16 is received into the head slider 36 to enter the magnetoresistive element 112 and thereby magnetize it. The magnetic flux passed through the magnetoresistive element 112 is absorbed by the first and second magnetic shields 104 and 106 .
- the resistance of the magnetoresistive element 112 changes with a change in the magnitude of the signal magnetic flux. Because a constant sense current is supplied from the sense current source to the magnetoresistive element 112 , the voltage between the pair of terminals of the magnetoresistive element 112 changes with changes in the resistance. Thus, the information recorded on the magnetic disk 16 can be reproduced as a voltage signal.
- FIG. 7A is a detailed top plan view of the head assembly 34 shown in FIG. 3A
- FIG. 7B is a side view of the head assembly 34
- FIG. 8 is a detailed bottom plan view of the head assembly 34 .
- FIG. 7A the MR wiring pattern 54 and the coil wiring pattern 60 are not shown. These wiring patterns are covered with an insulating film 118 .
- a pair of through holes 120 are formed at a front end portion of the reinforcing plate 44 .
- the through holes 120 can be visually recognized through the slit 48 , so that the through holes 120 can be used as reference holes in positioning the head slider 36 on the gimbal 46 .
- the through holes 120 are visually recognized and the head slider 36 is automatically mounted on the gimbal 46 at a given position by an assembly robot.
- a damper member 122 is bonded to the lower surface of the reinforcing plate 44 .
- the damper member 122 may be a piece of double-sided adhesive tape, for example, and is used to improve the balance of the head assembly 34 .
- FIG. 9A there is shown a top plan view of a head assembly 34 ′ according to a second preferred embodiment of the present invention.
- FIG. 9B is a side view of the head assembly 34 ′.
- the head assembly 34 ′ has a suspension 38 ′ preferably formed of stainless steel.
- the suspension 38 ′ is integrally formed at its front end portion with a gimbal 126 by etching, for example.
- an MR wiring pattern and a coil wiring pattern are formed on the suspension 38 ′. These wiring patterns are covered with an insulating film 118 ′.
- a spacer 52 ′ is fixed to a base end portion of the suspension 38 ′, such as by spot welding, for example.
- the suspension 38 ′ is formed at its opposite side portions with a pair of ribs 124 for imparting rigidity to the suspension 38 ′.
- a damper member 122 such as a piece of double-sided adhesive tape, is bonded to the lower surface of the suspension 38 ′.
- FIG. 10 there is shown a side view of the head assembly 34 ′ in the condition that the spring portion 38 a of the suspension 38 ′ is roundedly bent.
- the spring portion 38 a of the suspension 38 ′ is roundedly bent by an angle ⁇ 1 as shown in FIG. 10. Thereafter, the head assembly 34 ′ is mounted into the magnetic disk drive.
- the bending angle ⁇ 1 is set to about 10° in a free condition where the head slider 36 is not restricted by the disk.
- the head slider 36 comes into pressure contact with the corresponding magnetic disk because of the bend of the spring portion 36 , so that the spring load of the spring portion 38 a is applied to the head slider 36 .
- the gimbal 126 is bent by an angle ⁇ 2 at its neck portion 128 continuous to the front end of the suspension 38 ′.
- the load point of the spring load is determined by the bending angle ⁇ 2 .
- the bending angle ⁇ 2 is preliminarily adjusted so that the load point coincides with the center of gravity of the head slider 36 .
- the bending angle ⁇ 2 is set larger than that in the conventional head assembly to thereby shift the load point from the center of gravity of the head slider 36 toward the air inlet end of the head slider 36 .
- the load point can be set to substantially coincide with the center of gravity of a plurality of pads (not shown) of the head slider 36 .
- the load point may be set to substantially coincide with an intersection of a longitudinally extending center line of the slider 36 and a transverse line connecting the pads formed near the air inlet end of the slider 36 .
- the present invention it is possible to eliminate the problem that the lower edge of the air outlet end of the slider may come into contact with the disk surface in the case of reverse rotation of the Hall-less spindle motor during the start of rotation of the disk drive. Accordingly, it is possible to reliably eliminate the problem that the spindle motor may be unable to start rotation because of an increased load.
Abstract
Description
- The present invention relates generally to a magnetic head assembly including a magnetic head slider having a plurality of pads, and more particularly to a magnetic head assembly capable of preventing stiction of a magnetic head slider to a magnetic disk during the start of rotation of the magnetic disk drive.
- In recent years, there is a desire for reducing the size and increasing the capacity of magnetic disk drives for use as external storage devices in computers. One method of increasing the capacity of the magnetic disk drive is to increase the number of magnetic disks mounted on a spindle, and in association therewith the spacing between the magnetic disks in recent magnetic disk drives has increasingly been reduced in order to reduce the overall height of the disk drive unit.
- In recent magnetic disk drives, flying type magnetic head sliders employing the contact start and stop (CSS) system are frequently used. In such flying type magnetic head sliders with the CSS system, the magnetic head slider comes into contact with the magnetic disk when the disk drive stops rotating, but whereas during rotation, the magnetic head slider is kept flying at a microscopic height from the disk surface by an air flow generated over the surface of the magnetic disk, which rotates at a high speed during the recording or reproduction of information.
- In flying type magnetic head sliders with the CSS system, an electromagnetic transducer (i.e., a magnetic head element) is built into the slider, which receives the air flow generated over the disk surface. To maintain the slider in position, it is supported by a suspension. Accordingly, when the magnetic disk is not being rotated, the slider (including the electromagnetic transducer) is in contact with the disk surface, whereas when the magnetic disk is rotated, an air bearing surface of the slider that is opposed to the magnetic disk receives an air flow generated by the rotation of the magnetic disk, and the slider flies a small distance either above or below the disk surface. As a result, the electromagnetic transducer built into the slider is moved over the disk surface while being supported by the suspension, and performs recording or reproduction of information on a given track.
- In a magnetic disk drive employing a conventional flying type magnetic head slider, a pair of rails are generally provided along opposite side portions of the surface of the magnetic head slider that opposes the disk surface. Each of these two rails includes a flat air bearing surface. Further, a tapering surface is formed on each rail at its air inlet end portion. The air bearing surface of each rail receives an air flow generated by the high-speed rotation of the magnetic disk, which makes the slider fly above (or below) the disk, maintaining a microscopic distance between the disk surface and the electromagnetic transducer.
- With the CSS system, a relatively steady microscopic flying height (in the submicron range) can be obtained when the disk is rotated at a constant speed. However, when the disk is not being rotated, the rail surfaces (air bearing surfaces) of the slider are in contact with the disk. Accordingly, when the magnetic disk drive starts or stops rotating, the air bearing surfaces slide on the surface of the magnetic disk. If the surface roughness of the magnetic disk is low (i.e., if the disk surface is relatively smooth), the contact area between the air bearing surfaces and the magnetic disk surface during periods of non-rotation is large, and there arises a stiction problem between the magnetic head slider and the magnetic disk during the start of rotation of the magnetic disk.
- To avoid stiction, the surface roughness of the magnetic disk has conventionally been increased to a suitable level. However, such increases in surface roughness have the drawback of causing an increase in the flying height. Thus, in order to reduce the flying height of the magnetic head slider in response to the requirement for high-density recording, the surface roughness of the magnetic disk needs to be decreased, even though such a decrease in roughness increases stiction in conventional devices.
- In general, to improve the durability of the magnetic disk, a protective film made of a hard material such as carbon, and a lubricating layer for reducing friction and wear of the protective film are formed on a recording layer of the disk. Due to the presence of the lubricating layer, friction and wear of the protective film can be reduced. However, when the disk stops rotating, there is a possibility that stiction between the disk and the slider may occur, preventing the disk drive from being restarted.
- In association with increases in the amount of information being processed, the developments in high density, large capacity, and compact size magnetic disk drives been remarkable, and the occurrence of stiction has been greatly highlighted as a cause of faulty operation of the disk drive. One of the reasons for such faulty operation is the use of spindle motors with reduced torque (because of their small size). Another reason for such faulty operation is the smoothing out of the disk surface in order to achieve high density recording.
- To prevent this stiction problem, it has been proposed to provide a plurality of pads, or projections, on the flying surfaces (i.e., air bearing surfaces) of the slider, thereby reducing the contact area between the slider and the disk surface (see Japanese Laid-Open Patent Application No. 8-89674, for example). In assembling a magnetic head assembly by mounting such a magnetic head slider having a plurality of pads upon a front end portion of a suspension formed of stainless steel, the magnetic head slider is mounted on the front end portion of the suspension so that its load point (the point where the spring load of the suspension is applied to the magnetic head slider) coincides with the center of gravity of the magnetic head slider.
- At present, a three-phase Hall-less motor employing no Hall element is generally used as the motor for rotating the spindle. In a CSS type magnetic disk drive, the magnetic head slider comes into contact with the magnetic disk when the disk drive is powered off, as mentioned above. Upon restarting the disk drive, a current is passed through any one of the three-phase coils to position the coil near a permanent magnet. At this time, the motor is rotated in either the forward direction or the reverse direction, depending upon the positional relationship between the coil and the permanent magnet upon stopping of the disk drive, so that the motor is rotated forwardly or reversely by about 60° to position the coil near the permanent magnet. After this positioning, the current passing through each phase is controlled to be switched, thereby continuously rotating the motor in the forward direction. In this manner, the rotating direction of the motor is determined according to the positional relationship between the coil and the permanent magnet upon stopping of the disk drive. Accordingly, the initial reverse rotation of the motor occurs with a probability of about 50%.
- In the case of a magnetic head slider having pads formed on an air bearing surface, it has been found that such reverse rotation of the motor causes the following problem, which will now be described with reference to FIG. 1, which is a schematic side view of a
magnetic head slider 2 parked on amagnetic disk 4. In FIG. 1, an arrow R. denotes the forward rotating direction of themagnetic disk 4, and an arrow R. denotes the reverse rotating direction of themagnetic disk 4. Two pads 6 are formed on the air bearing surfaces of thehead slider 2 near the air inlet end of thehead slider 2, although only one pad 6 is shown in the FIG. 1 view. Similarly, two pads 8 are formed on the air bearing surfaces of thehead slider 2 at an intermediate position between the air inlet end and the air outlet end of thehead slider 2, although only one is shown in FIG. 1. In particular, the pad 8 that is formed on the air bearing surface where a head element (transducer) is formed is located at a substantially longitudinally central position of thehead slider 2. The reason for locating the pad 8 in such a position is to minimize the spacing between the head element and themagnetic disk 4 during flying of themagnetic head slider 2, thereby reducing wasted space and preventing projection of the pad 8 beyond the minimum flying height of themagnetic head slider 2. -
Reference numeral 10 denotes the center of gravity of theslider 2, about which moments are generated when the spindle is rotated. When the spindle is rotated in the forward direction, a clockwise moment M1 (as viewed in FIG. 1) is generated. This clockwise moment M1 causes the pads 6 to be pressed against themagnetic disk 4. In this case, the overhang of theslider 2 that projects between the pads 6 and the lower edge of the air inlet end of theslider 2 is small, so that there is little possibility that this lower edge of the air inlet end of theslider 2 will come into contact with the recording surface of themagnetic disk 4. In other words, ifslider 2 is rotated in direction M1, there is little chance that its lower right hand comer (as shown in FIG. 1) will contact thedisk 4. - However, when the spindle is reversely rotated during positioning of the coil and the magnet in the Hall-less motor, a counterclockwise moment M2 (as viewed in FIG. 1) is generated. This counterclockwise moment M2 causes the pads 8 and the surfaces on the left-hand side of the
slider 2 to be pressed against themagnetic disk 4. As shown in FIG. 1, the overhang of theslider 2 that projects between the pads 8 and the lower edge of the air outlet end of theslider 2 is large, so that there is a significant possibility that this lower edge of the air outlet end of theslider 2 will come into contact with the recording surface of themagnetic disk 4, resulting in an increase in the frictional force between theslider 2 and themagnetic disk 4. In this case, the lower edge ofslider 2 being referred to is that shown at the lower left-hand corner, as shown in FIG. 1. Such contact between the lower edge of theslider 2 and themagnetic disk 4 may hinder the ability of the spindle to smoothly start rotating thedisk 4. - It is accordingly an object of the present invention to provide a head assembly which can minimize or prevent contact between the slider edges and the disk surface, which prevents increasing the frictional force between the head slider and the recording medium, even during reverse rotation of the spindle motor, during start-up of the disk drive.
- It is another object of the present invention to provide a disk drive which can improve the recording density by using a recording medium which has a smooth recording surface, while still reducing the spacing between the head element and the recording medium.
- Briefly, the present invention provides an improved head assembly in which contact between the slider edges and the disk medium is eliminated, or at least minimized, even during reverse rotation, by changing the location of where the spring load is applied to the slider. If the spring load is moved from the center of gravity of the slider to a position between the center of gravity of the slider and the air inlet end of the slider, a moment is created that reduces the effects of the counterclockwise moment M2 (see FIG. 1), whereby counterclockwise rotation of the slider that may occur when the disk medium is rotated in the reverse direction is reduced or eliminated. Accordingly, with the present invention, the probability of contact between the outer edge of the slider and the disk is reduced.
- More specifically, the present invention relates to a head assembly (or a disk drive with such a head assembly) that includes a suspension having a roundedly bent portion for generating a spring load with a gimbal located on that suspension, and where the suspension has a slider mounting portion thereon. Additionally, there is a head slider mounted on the slider mounting portion of said gimbal, and the head slider includes an air bearing surface, an air inlet end, and an air outlet end. The spring load of the suspension is applied to the head slider at a load point that is offset from a center of gravity of the head slider, such that the offset load point is located between the center of gravity of the head slider and the air inlet end of said head slider.
- Preferably, the head slider also includes several pads extending from its air bearing surface, and the offset load point of the spring load of the suspension is preferably set to substantially coincide with a center of gravity of the plurality of pads. Alternatively, the offset load point may be set to substantially coincide with a position lying on a straight line connecting two of the pads formed near the air inlet end.
- There are at least two different configurations for realizing the offset load point of the present invention. The first configuration includes a reinforcing plate connected to the suspension, and a pivot formed on the reinforcing plate and kept in pressure contact with the slider mounting portion of the gimbal, such that the pivot applies the spring load of the suspension to the head slider. In the second configuration, the gimbal is bent at a neck portion thereof by a given angle with respect to the suspension such that the spring load of the suspension is applied to the head slider at the offset load point.
- Preferred embodiments of the present invention are described herein with reference to the drawings wherein:
- FIG. 1 is a side view of a magnetic head slider, for illustrating a problem in the prior art;
- FIG. 2 is a perspective view of a magnetic disk drive of the present invention with its cover removed;
- FIG. 3A is a perspective view of a head assembly according to a first preferred embodiment of the present invention;
- FIG. 3B is a longitudinal sectional view of the head assembly shown in FIG. 3A;
- FIG. 4 is a plan view of a head slider of the head assembly shown in FIG. 3A;
- FIG. 5A is a side view of the head slider in its flying condition, showing its pitch angle;
- FIG. 5B is an end view of the head slider in its flying condition, showing its roll angle;
- FIG. 6 is a sectional view of an essential part of an MR head mounted on the head slider;
- FIG. 7A is a top plan view of the head assembly according to the first preferred embodiment of the present invention, showing details not visible in FIGS. 3A and 3B;
- FIG. 7B is a side view of the head assembly shown in FIG. 7A;
- FIG. 8 is a bottom plan view of the head assembly shown in FIG. 7A;
- FIG. 9A is a top plan view of a head assembly according to a second preferred embodiment of the present invention;
- FIG. 9B is a side view of the head assembly shown in FIG. 9A;
- FIG. 10 is a side view of the head assembly according to the second preferred embodiment showing the spring portion with rounded bend therein.
- Referring to FIG. 2, there is shown a perspective view of a magnetic disk drive with its cover removed.
Reference numeral 12 denotes a base. Ashaft 14 is fixed to thebase 12. A spindle hub (not shown) is rotatably mounted on theshaft 14 so as to be driven by a Hall-less spindle motor (not shown). - A plurality of
magnetic disks 16 and spacers (not shown) are mounted on the spindle hub in such a manner as to be alternately stacked. That is, the pluralmagnetic disks 16 are fixedly mounted on the spindle hub by securing adisk clamp 18 to the spindle hub by a plurality ofscrews 20, and thesedisks 16 are equally spaced apart at a given distance by the spacers. -
Reference numeral 22 denotes a rotary actuator consisting of anactuator arm assembly 24 and amagnetic circuit 26. Theactuator arm assembly 24 is mounted so as to be rotatable about ashaft 28, which is fixed to thebase 12. - The
actuator arm assembly 24 includes anactuator block 30 that is rotatably mounted on theshaft 28 through a pair of bearings. Theactuator arm assembly 24 further includes a plurality ofactuator arms 32 that extend from theactuator block 30 in one direction, and ahead assembly 34 that is fixed to a front end portion of eachactuator arm 32. - Each
head assembly 34 includes ahead slider 36 that has a head element (i.e., such as an electromagnetic transducer or an optical element) for reading/writing data from/to the correspondingmagnetic disk 16, and asuspension 38 that has a front end portion for supporting thehead slider 36 and a base end portion fixed to the correspondingactuator arm 32. A coil (not shown) is supported on theactuator block 30 the opposite side from where theactuator arms 32 extend from. Themagnetic circuit 26 and the coil, which is inserted into a gap in themagnetic circuit 26, constitute a voice coil motor (VCM) 40. -
Reference numeral 42 denotes a flexible printed circuit board (FPC) for supplying a write signal to the magnetic head element and for taking a read signal from the magnetic head element. The flexible printedcircuit board 42 is fixed at one end to a side surface of theactuator block 30. - FIG. 3A is a perspective view of a
head assembly 34 according to a first preferred embodiment of the present invention, and FIG. 3B is a longitudinal sectional view of thehead assembly 34 shown in FIG. 3A. -
Reference numeral 38 denotes a suspension, which may be formed of stainless steel, for example. Thesuspension 38 includes aspring portion 38 a and arigid portion 38 b. A reinforcingplate 44 is spot-welded to the lower surface of therigid portion 38 b of thesuspension 38. - In the preferred embodiment, the total length of the
head assembly 34 is approximately 16.0 mm, and its maximum width is approximately 4.4 mm at its base end where aspacer 52 is affixed. Thesuspension 38 preferably has a thickness of approximately 22 μm and a weight of approximately 2.4 mg. Note that the preceding dimensions were given for the purposes of illustration only, and it is contemplated that alternate dimensions may also be utilized without departing from the spirit of the invention. - The
suspension 38 preferably includes an integrally formedgimbal 46, located near its front end. Thisgimbal 46 is created by a substantiallyU-shaped slit 48 formed at the front end portion of thesuspension 38 which thereby defines thegimbal 46 inside of theslit 48. Amagnetic head slider 36 is fixed to the upper surface of thegimbal 46 by an adhesive or the like. - The spacer52 (which is used for fixing the
head assembly 34 to the corresponding actuator arm 34) is preferably fixed to the base end portion of thesuspension 38 by spot welding. Apivot 50 is formed at a front end portion of the reinforcingplate 44. Thepivot 50 is in contact with the lower surface of thegimbal 46 to thereby support themagnetic head slider 36. The reinforcingplate 44 preferably has a total length of approximately 5.0 mm, a maximum width of approximately 2.0 mm, a thickness of approximately 30 μm, and an approximate weight of 1.4 mg, although other dimensions and weights are also contemplated as being within the scope of the invention. - The
pivot 50 preferably has a height of approximately 50 μm, and themagnetic head slider 36 preferably has a length of approximately 1.2 mm, a width of approximately 1.0 mm, a height of approximately 0.3 mm, and a weight of approximately 1.6 mg. Although, once again, other dimensions and weights are also contemplated. - As shown in FIG. 3B, the
gimbal 46 is slightly raised above the upper surface of thesuspension 38 by thepivot 50. Accordingly, a preload F is applied to thegimbal 46 when thehead slider 36 is in an unloaded condition (i.e., when the slider is not loaded onto the magnetic disk). In this condition, thegimbal 46 is maintained substantially parallel with thesuspension 38. - During mounting of the
head assembly 34 into the magnetic disk drive, thespring portion 38 a of thesuspension 38 is bent to form a generally rounded bend as shown in FIG. 10. By bending thespring portion 38 a in this rounded manner, the spring load of thespring portion 38 a is applied through thepivot 50 to thehead slider 36 when thehead assembly 34 is mounted in the magnetic disk drive. That is, the tip of thepivot 50 falls at a load point of the spring load. - As shown in FIG. 3A, an
MR wiring pattern 54 and acoil wiring pattern 60 are formed by printing upon the upper surface of thesuspension 38. TheMR wiring pattern 54 consists of a pair oflead lines coil wiring pattern 60 consists of a pair oflead lines - The lead lines56 and 58 have first ends respectively connected to the terminals of a magnetoresistive element (MR element, which will hereinafter be described) in the
magnetic head slider 36 by bonding throughgold balls 66. On the other hand, the lead lines 62 and 64 have first ends respectively connected to the terminals of a coil (which will hereinafter be described) in themagnetic head slider 36 by bonding throughgold balls 68. - A
tab 70 is formed at one side edge of thesuspension 38, and fourterminals tab 70. Theterminals - Referring now to FIG. 4, there is shown a plan view of the
magnetic head slider 36 used in thehead assembly 34. A pair ofrails slider 36 that will oppose the surface of the magnetic disk. Therails rails groove 86 is defined between therails - A
head element 88 is formed on the air outlet end of theslider 36 at a transverse position adjacent to therail 80. Acenter rail 84 is formed between therails slider 36. - Each of the
rails slider 36 makes it possible to minimize variations in flying height when dust is present upon the magnetic disk. - Two
pads rail 80, and twopads rail 82. Thepads - The
pads slider 36 at the same position with respect to the longitudinal axis of theslider 36.Pad 90 extends across the boundary between the air bearing surface 80 a and the taperingsurface 80 b. Similarly,pad 94 extends across the boundary between the air bearing surface 82 a and the taperingsurface 82 b. - On the other hand, the
pads pads slider 36 at such positions where thepads slider 36. - More specifically, the
pad 92 formed on therail 80 is preferably shifted toward the air inlet end of theslider 36 in comparison with thepad 96 formed on therail 82. The positions of thepads rail 80 adjacent to thehead element 88 is set to be lower than the flying height of therail 82. The flying height of therail 80 can be made smaller than the flying height of therail 82 by setting the width of therail 80 to be less than the width of therail 82, as shown in FIG. 4. - Referring to FIGS. 5A and 5B, the flying attitude of the
head slider 36 is shown. Thehead slider 36 is so designed as to have a pitch angle A shown in FIG. 5A and a roll angle B shown in FIG. 5B during its flying condition so that thehead element 88 comes closest to the minimum flying height 98 shown by the dashed line. Furthermore, the positions and heights of thepads slider 36. - The pitch angle A is defined as an angle between the longitudinal axis of the
slider 36 and a line denoting the minimum flying height 98 during the flying condition of theslider 36 as shown in FIG. 5A, whereas the roll angle B is defined as an angle between a transverse line of theslider 36 and a line denoting the minimum flying height 98 during the flying condition of theslider 36 as shown in FIG. 5B. In the preferred embodiment, the pitch angle A is preferably between 50-200 microradians (and is more preferably between 90-150 microradians), and the roll angle B is preferably between 10-80 microradians (and is more preferably between 20-40 microradians). - Referring again to FIG. 4, reference symbol G1 denotes the center of gravity of the
head slider 36. In a conventional head assembly, thehead slider 36 is mounted on a suspension so that the load point of the spring load of the suspension coincides with the center of gravity G1 of thehead slider 36. - However, such a slider mounting structure in the conventional head assembly has a problem such that if the Hall-less spindle motor is reversely rotated during the start of the rotation of the disk, the lower edge of the air outlet end of the
head slider 36 often comes into contact with the magnetic disk surface as mentioned previously. - To solve this problem, in the present invention the
pivot 50 is positioned relative to thehead slider 36 when fixed to thegimbal 46 so that the load point of thespring portion 38 a of thesuspension 38 is shifted from the center of gravity G1 of theslider 36 toward the air inlet end of theslider 36. - By setting the position of the
pivot 50 closer to the air inlet end as mentioned above, there is generated a moment canceling the moment M2 about the center of gravity G1 of theslider 36 generated by reverse rotation of the spindle as shown in FIG. 1, thereby solving the problem that the lower edge of the air outlet end of theslider 36 may come into contact with the magnetic disk surface at starting the disk drive. - Preferably, the load point is set to coincide with a center of gravity G2 of the
pads pads 90 to 96, thereby preventing abnormal wearing of thepads 90 to 96 due to nonuniform contact of thepads 90 to 96 with the magnetic disk surface. Accordingly, it is possible to reduce the wear of each pad due to CSS and to obtain stable flying start characteristics. - As a modification, the load point may be set to coincide with an intersection F of a longitudinally extending center line of the
slider 36 and a transverse line connecting thepads slider 36. By shifting the load point to such a position near the air inlet end of theslider 36, it is possible to effectively solve the problem that the lower edge of the air outlet end of theslider 36 may come into contact with the magnetic disk surface. In this preferred embodiment, the load point is determined by the position of thepivot 50 relative to theslider 36. - As shown in FIG. 6, the
magnetic head slider 36 has aconductive substrate 100 and a nonmagnetic insulatinglayer 102 formed on theconductive substrate 100. The nonmagnetic insulatinglayer 102 may be formed of alumina (Al2O3), for example. - First and second
magnetic shields 104 and 106, which may be formed of nickel-iron (Ni—Fe), for example, are embedded in the nonmagnetic insulatinglayer 102. Agap 108 for improving the reproductive resolution is defined between the first and secondmagnetic shields 104 and 106 on a front end surface (i.e., the medium opposing surface) 110 of thehead slider 36. - A magnetoresistive element (MR element)112, which may be formed of nickel-iron (Ni—Fe), is embedded in the
gap 108 so as to be exposed to thefront end surface 110 of thehead slider 36. Although not shown, a sense current source is connected to a pair of terminals of themagnetoresistive element 112 to supply a constant sense current to themagnetoresistive element 112. -
Reference numeral 116 denotes a magnetic pole having one end exposed to thefront end surface 110 of thehead slider 36 and the other end connected to the secondmagnetic shield 106. Aconductor coil 114 is wound substantially around a connected portion between themagnetic pole 116 and the secondmagnetic shield 106. - By passing a current modulated by information to be recorded through the
coil 114, a magnetic field having a strength corresponding to the amperage of the modulated current is induced to thereby magnetically record the information on a recording track of themagnetic disk 16. - In reading information recorded on the
magnetic disk 16, themagnetoresistive element 112 is used. That is, a signal magnetic flux from a recording track of themagnetic disk 16 is received into thehead slider 36 to enter themagnetoresistive element 112 and thereby magnetize it. The magnetic flux passed through themagnetoresistive element 112 is absorbed by the first and secondmagnetic shields 104 and 106. - The resistance of the
magnetoresistive element 112 changes with a change in the magnitude of the signal magnetic flux. Because a constant sense current is supplied from the sense current source to themagnetoresistive element 112, the voltage between the pair of terminals of themagnetoresistive element 112 changes with changes in the resistance. Thus, the information recorded on themagnetic disk 16 can be reproduced as a voltage signal. - FIG. 7A is a detailed top plan view of the
head assembly 34 shown in FIG. 3A, and FIG. 7B is a side view of thehead assembly 34. FIG. 8 is a detailed bottom plan view of thehead assembly 34. - In FIG. 7A, the
MR wiring pattern 54 and thecoil wiring pattern 60 are not shown. These wiring patterns are covered with an insulatingfilm 118. - As shown in FIG. 7A, a pair of through
holes 120 are formed at a front end portion of the reinforcingplate 44. The throughholes 120 can be visually recognized through theslit 48, so that the throughholes 120 can be used as reference holes in positioning thehead slider 36 on thegimbal 46. In assembling thehead assembly 34, the throughholes 120 are visually recognized and thehead slider 36 is automatically mounted on thegimbal 46 at a given position by an assembly robot. - As shown in FIGS. 7B and 8, a
damper member 122 is bonded to the lower surface of the reinforcingplate 44. Thedamper member 122 may be a piece of double-sided adhesive tape, for example, and is used to improve the balance of thehead assembly 34. - Referring to FIG. 9A, there is shown a top plan view of a
head assembly 34′ according to a second preferred embodiment of the present invention. FIG. 9B is a side view of thehead assembly 34′. Thehead assembly 34′ has asuspension 38′ preferably formed of stainless steel. Thesuspension 38′ is integrally formed at its front end portion with agimbal 126 by etching, for example. - Like the first preferred embodiment mentioned above, an MR wiring pattern and a coil wiring pattern (both not shown) are formed on the
suspension 38′. These wiring patterns are covered with an insulatingfilm 118′. - A
spacer 52′ is fixed to a base end portion of thesuspension 38′, such as by spot welding, for example. Thesuspension 38′ is formed at its opposite side portions with a pair ofribs 124 for imparting rigidity to thesuspension 38′. Adamper member 122, such as a piece of double-sided adhesive tape, is bonded to the lower surface of thesuspension 38′. - Referring to FIG. 10, there is shown a side view of the
head assembly 34′ in the condition that thespring portion 38 a of thesuspension 38′ is roundedly bent. In mounting thehead assembly 34′ into the magnetic disk drive, thespring portion 38 a of thesuspension 38′ is roundedly bent by an angle θ1 as shown in FIG. 10. Thereafter, thehead assembly 34′ is mounted into the magnetic disk drive. - The bending angle θ1 is set to about 10° in a free condition where the
head slider 36 is not restricted by the disk. When thehead assembly 34′ is mounted into the magnetic disk drive, thehead slider 36 comes into pressure contact with the corresponding magnetic disk because of the bend of thespring portion 36, so that the spring load of thespring portion 38 a is applied to thehead slider 36. - The
gimbal 126 is bent by an angle θ2 at itsneck portion 128 continuous to the front end of thesuspension 38′. The load point of the spring load is determined by the bending angle θ2. In a conventional head assembly, the bending angle θ2 is preliminarily adjusted so that the load point coincides with the center of gravity of thehead slider 36. - In the
head assembly 34′ according to this preferred embodiment, the bending angle θ2 is set larger than that in the conventional head assembly to thereby shift the load point from the center of gravity of thehead slider 36 toward the air inlet end of thehead slider 36. - For example, by setting the bending angle θ2 to 3.45°, the load point can be set to substantially coincide with the center of gravity of a plurality of pads (not shown) of the
head slider 36. Like the first preferred embodiment, the load point may be set to substantially coincide with an intersection of a longitudinally extending center line of theslider 36 and a transverse line connecting the pads formed near the air inlet end of theslider 36. - According to the present invention, it is possible to eliminate the problem that the lower edge of the air outlet end of the slider may come into contact with the disk surface in the case of reverse rotation of the Hall-less spindle motor during the start of rotation of the disk drive. Accordingly, it is possible to reliably eliminate the problem that the spindle motor may be unable to start rotation because of an increased load.
- Accordingly, by using a magnetic disk having a smooth recording surface, the spacing between the head and the disk can be reduced, thereby contributing to an increase in recording density of a disk drive.
- While various embodiments of the present invention have been shown and described, it should be understood that other modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art. Such modifications, substitutions and alternatives can be made without departing from the spirit and scope of the invention, which should be determined from the appended claims.
- Various features of the invention are set forth in the appended claims.
Claims (17)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP36790398A JP3815094B2 (en) | 1998-12-24 | 1998-12-24 | Head assembly and disk device |
JP10-367903 | 1998-12-24 |
Publications (2)
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US20010028536A1 true US20010028536A1 (en) | 2001-10-11 |
US6417992B2 US6417992B2 (en) | 2002-07-09 |
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US09/358,334 Expired - Fee Related US6417992B2 (en) | 1998-12-24 | 1999-07-21 | Head assembly and disk drive |
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US (1) | US6417992B2 (en) |
JP (1) | JP3815094B2 (en) |
KR (1) | KR100632314B1 (en) |
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DE (1) | DE19942497A1 (en) |
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JP3675508B2 (en) * | 1995-01-24 | 2005-07-27 | 株式会社東芝 | Recording / reproducing head slider and recording / reproducing apparatus using the same |
JPH08321027A (en) | 1995-05-25 | 1996-12-03 | Hitachi Ltd | Magnetic head and magnetic recording and reproducing device |
JP3426082B2 (en) * | 1996-04-26 | 2003-07-14 | 富士通株式会社 | Magnetic head slider and magnetic disk drive |
JP3240935B2 (en) * | 1996-09-20 | 2001-12-25 | 株式会社日立製作所 | Magnetic disk drive |
US5870251A (en) * | 1997-04-14 | 1999-02-09 | Seagate Technology, Inc. | Taperless/crown free/air bearing design |
US5850320A (en) * | 1997-05-13 | 1998-12-15 | Seagate Technology, Inc. | Head-gimbal assembly with reduced vertical spacing envelope and alignment structures |
GB2366657B (en) * | 1997-06-27 | 2002-04-24 | Seagate Technology Llc | Slider for disc storage system |
JPH1186483A (en) * | 1997-09-04 | 1999-03-30 | Fujitsu Ltd | Head slider and disk device |
US6215621B1 (en) * | 1997-11-07 | 2001-04-10 | Seagate Technology Llc | Multi-tier bearing with deposited tier |
US6243222B1 (en) * | 1998-03-20 | 2001-06-05 | Seagate Technology, Inc | Load/unload method for sliders in a high speed disk drive |
US6188547B1 (en) * | 1998-06-04 | 2001-02-13 | Seagate Technology Llc | Slider with pressure relief trenches |
US6236543B1 (en) * | 1999-01-29 | 2001-05-22 | Read-Rite Corporation | Durable landing pads for an air-bearing slider |
-
1998
- 1998-12-24 JP JP36790398A patent/JP3815094B2/en not_active Expired - Fee Related
-
1999
- 1999-07-21 US US09/358,334 patent/US6417992B2/en not_active Expired - Fee Related
- 1999-07-30 KR KR1019990031348A patent/KR100632314B1/en not_active IP Right Cessation
- 1999-08-10 CN CNB99117528XA patent/CN1226737C/en not_active Expired - Fee Related
- 1999-09-06 DE DE19942497A patent/DE19942497A1/en not_active Withdrawn
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US20040148619A1 (en) * | 2003-01-23 | 2004-07-29 | Samsung Electronics Co., Ltd. | Optical Actuator |
US7131128B2 (en) * | 2003-01-23 | 2006-10-31 | Samsung Electronics Co., Ltd. | Optical actuator |
US20060203390A1 (en) * | 2005-03-11 | 2006-09-14 | Walton Fong | Apparatus and method for modifying the air bearing force of the trailing edge of a slider to increase head to disk interface reliability for contact recording systems |
US20060203393A1 (en) * | 2005-03-11 | 2006-09-14 | Walton Fong | Apparatus and method for reducing a suspension gram load to increase head to disk interface reliability for contact recording systems |
US20060203394A1 (en) * | 2005-03-11 | 2006-09-14 | Walton Fong | Apparatus and method for utilizing an off-center gimbal to increase head to disk interface reliability for contact recording systems |
US20060203392A1 (en) * | 2005-03-11 | 2006-09-14 | Walton Fong | Method and apparatus for modifying a slider to increase head to disk interface reliability for contact recording systems |
US8014105B2 (en) | 2005-03-11 | 2011-09-06 | Hitachi Global Storage Technologies, Netherlands B.V. | Method and apparatus for modifying the air bearing force of the trailing edge of a slider to increase head to disk interface reliability for contact recording systems |
US7345850B2 (en) | 2005-03-11 | 2008-03-18 | Hitachi Global Storage Technologies Netherlands, B.V. | Method and apparatus for utilizing an off-center gimbal to increase head to disk interface reliability for contact recording systems |
US7352530B2 (en) | 2005-03-11 | 2008-04-01 | Hitachi Global Storage Technologies Netherlands B.V. | Method and apparatus for reducing a suspension gram load to increase head to disk interface reliability for contact recording systems |
US8014106B2 (en) | 2005-03-11 | 2011-09-06 | Hitachi Global Storage Technologies, Netherlands B.V. | Method and apparatus for modifying a dynamic pitch of a slider to increase head to disk interface reliability for contact recording systems |
US7737365B2 (en) * | 2006-06-22 | 2010-06-15 | Nitto Denko Corporation | Wired circuit board |
US20090183907A1 (en) * | 2006-06-22 | 2009-07-23 | Nitto Denko Corporation | Wired circuit board |
US20070295534A1 (en) * | 2006-06-22 | 2007-12-27 | Nitto Denko Corporation | Wired circuit board |
US8247700B2 (en) | 2006-06-22 | 2012-08-21 | Nitto Denko Corporation | Wired circuit board |
US20170025148A1 (en) * | 2012-08-27 | 2017-01-26 | Michael Boyd | Calibrated Device And Method to Detect Material Features on a Spinning Surface by Generation and Detection of Gravito-magnetic Energy |
US20170054389A1 (en) * | 2012-08-27 | 2017-02-23 | Michael Boyd | Device And Method to Generate and Capture of Gravito-magnetic Energy |
US9972354B2 (en) * | 2012-08-27 | 2018-05-15 | Michael Boyd | Calibrated device and method to detect material features on a spinning surface by generation and detection of gravito-magnetic energy |
US10177690B2 (en) * | 2012-08-27 | 2019-01-08 | Michael Boyd | Device and method to generate and capture of gravito-magnetic energy |
US11496033B2 (en) | 2019-01-08 | 2022-11-08 | Michael Boyd | Device and method to generate and apply gravito-magnetic energy |
CN113906656A (en) * | 2019-05-28 | 2022-01-07 | Lg伊诺特有限公司 | Motor |
Also Published As
Publication number | Publication date |
---|---|
JP3815094B2 (en) | 2006-08-30 |
JP2000195208A (en) | 2000-07-14 |
KR100632314B1 (en) | 2006-10-11 |
US6417992B2 (en) | 2002-07-09 |
CN1258074A (en) | 2000-06-28 |
CN1226737C (en) | 2005-11-09 |
KR20000047449A (en) | 2000-07-25 |
DE19942497A1 (en) | 2000-07-06 |
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