JP5576105B2 - Disk drive - Google Patents

Description

  The present invention relates to a disk drive, and more particularly to a discharge prevention technique between a head slider and a disk.

  As a disk drive device, a device using a recording disk of various modes such as an optical disk, a magneto-optical disk, or a flexible magnetic disk is known. Among them, a hard disk drive (HDD) is a memory of a computer. Besides being widely used as a device, it is used in many electronic devices such as a moving image recording / reproducing device or a car navigation system.

  A magnetic disk used in the HDD has a plurality of data tracks and a plurality of servo tracks. In each data track, one or a plurality of data sectors including user data are recorded. Each servo track has address information. The servo track is composed of a plurality of servo data spaced apart in the circumferential direction, and one or a plurality of data sectors are recorded between each servo data. When the head element unit accesses a desired data sector according to the address information of the servo data, data writing to the data sector and data reading from the data sector can be performed.

  The head element portion is formed on a slider, and the slider is fixed on the suspension of the actuator. The assembly of the suspension and the head slider is called a head gimbal assembly (HGA). The assembly of the actuator and the head slider is called a head stack assembly (HSA).

  The head slider floats on the magnetic disk by balancing the pressure of the air between the slider flying surface facing the magnetic disk and the rotating magnetic disk with the pressure applied in the direction of the magnetic disk by the suspension. To do. As the actuator rotates about the rotation axis, the head slider (head element portion) moves to the target track and is positioned on the track.

  The magnetic disk is fixed to a spindle motor, and the magnetic disk is charged by the rotation of the spindle motor. The magnetic disk is connected to the system ground via a spindle motor, but there is a limit to reducing the resistance between the system ground and the magnetic disk, and it is difficult to reduce the magnetic disk potential to 0V. It is. In particular, recent spindle motors have a hydrodynamic bearing structure. Since the conductivity of the oil used in the fluid bearing is low, it is more difficult to remove the charge by connecting the magnetic disk to the system ground.

  When the magnetic disk is charged, charges of opposite polarity are induced on the surface of the head slider flying over the magnetic disk, and a potential difference is generated between the magnetic disk and the head slider. If a large potential difference exists between the head slider and the magnetic disk, arc discharge may occur between the magnetic disk and the head slider, and the head element unit may be damaged. For this reason, for example, a technique has been proposed in which the reference voltage of the read element drive circuit is set to the same potential as the magnetic disk potential (see, for example, Patent Document 1).

JP 2007-250102 A

  The actuator that supports the head slider rotates on the rotating magnetic disk, thereby moving the head slider on the magnetic disk in the disk radial direction. The inventors have found that the occurrence probability of the head-disk discharge changes depending on the operation of the head slider (actuator) on the magnetic disk. Specifically, the head-disk discharge is likely to occur when the head slider moves on the magnetic disk, that is, when the actuator rotates on the magnetic disk.

  According to the study by the inventors, it has been found that this is due to a change in the projected area of the actuator on the magnetic disk. 6A and 6B show the actuator 61 at different disk radial positions, respectively. FIG. 6A shows the HSA at the innermost circumferential position, and FIG. 6B shows the actuator 61 at the position immediately before unloading where the tip of the actuator is in contact with the ramp 62. 6A and 6B, in order to clarify the overlapping position of the magnetic disk 63 and the actuator 61, the outer peripheral edge of the magnetic disk is clearly shown.

  As can be understood by comparing FIG. 6A and FIG. 6B, the projected area of the actuator 61 onto the magnetic disk 63 becomes smaller as the actuator 61 moves to the outer peripheral side. For this reason, the electrostatic capacitance between the actuator and the magnetic disk decreases as it goes to the outer circumference side of the disk. FIG. 7 is a graph showing a change in actuator projection area with respect to a magnetic disk according to a disk radius position and a change in head-disk voltage with a disk radius position in a conventional HDD. Both the projected area and the head-disk voltage are standard values. As shown in FIG. 7, the projected area decreases and the head-disk voltage increases as the position moves from the innermost peripheral position on the recording surface to the outermost peripheral position.

  The decrease in capacitance means an increase in voltage between the head slider and the magnetic disk. Thus, in addition to the large head-disk voltage on the outer peripheral side, the head-disk voltage varies depending on the disk radius position, which causes the head-disk discharge. Therefore, a technique that can effectively suppress the occurrence of discharge between the head and the disk in the movement between the inner peripheral side and the outer peripheral side of the actuator (head slider) is desired.

  A disk drive according to an aspect of the present invention includes a disk that stores data, a head slider that floats on the disk, and the head slider that supports the head slider and rotates on a rotation shaft. And an actuator that moves in the radial direction of the disk. The actuator includes a suspension that supports the head slider, and an arm that is disposed between the suspension and the rotation shaft, supports the suspension, and is formed of metal. The arm is opposed to the disk at the innermost circumferential position of the area where the head slider is levitated by a flying force on the rotating disk, and the arm is positioned at the outermost circumferential position of the area. An outer peripheral side region on the outer side, and an inner peripheral side of the outer peripheral side region, and an inner peripheral side region facing the disk between the innermost peripheral position and the outermost peripheral position. The electrostatic capacity per unit area between the outer peripheral side region and the disk at the innermost peripheral position is the electrostatic capacity per unit area between the inner peripheral region and the disk at the innermost peripheral position. Smaller than capacity. With this configuration, it is possible to suppress the occurrence of discharge between the head slider and the disk.

In a preferred configuration, a dielectric sheet is attached to a surface of the arm facing the disk in the inner peripheral region. Thereby, the capacitance of the arm can be adjusted without greatly changing the arm shape.
The dielectric sheet is preferably attached only to the inner peripheral region. Thereby, the capacitance of the arm can be adjusted efficiently.

  The dielectric sheet is preferably formed of a material having a relative dielectric constant of 9 or more. As a result, by reducing the area of the dielectric sheet, it is possible to obtain a desired capacitance in the arm inner peripheral region while reducing the influence on the dynamics.

In a preferred configuration, a hole is formed in the outer peripheral region. Thereby, the electrostatic capacitance per unit area of the arm outer peripheral side region can be effectively reduced.
In a more preferred configuration, a plurality of holes are formed in the outer peripheral region. Thereby, the fall of arm intensity | strength can be made small.

  In a preferred configuration, the amount of decrease in the electrostatic capacity of the outer peripheral region in the movement from the innermost peripheral position to the outermost peripheral position is the sum of the inner peripheral region and the outer peripheral region at the innermost peripheral position. 5% or less of the capacitance between the remaining area and the disk. Thereby, the head-disk discharge can be prevented more effectively.

  In a preferred configuration, the apparatus further includes a plate that faces the disk and suppresses airflow caused by rotation of the disk, and the plate is a metal part and a dielectric formed on a surface of the metal part facing the disk. Part. As a result, the change due to the radial position of the head-disk voltage can be reduced, and the amount of reduction in the capacitance change required in the actuator design can be reduced.

  According to the present invention, the occurrence of discharge between the head slider and the disk can be suppressed.

In this embodiment, it is a top view which shows the internal structure of HDD which removed the cover of the housing | casing. In this embodiment, it is a figure which shows typically the state in which the actuator which has a hole in an arm is located in the innermost peripheral position on a magnetic disc. In this embodiment, it is a figure which shows typically the state in which the actuator which has a hole in an arm is located in the outermost periphery position on a magnetic disc. In this embodiment, it is a figure which shows typically the state which the actuator with which the dielectric material sheet adhered to the arm is located in the innermost periphery position on a magnetic disc. In this embodiment, it is a figure which shows typically the state which the actuator with which the dielectric material sheet adhered to the arm is located in the outermost periphery position on a magnetic disc. In this embodiment, it is a figure which shows typically the state which has a hole in an arm, and also has an actuator which has a dielectric sheet adhering to an arm located in the innermost periphery position on a magnetic disc. In this embodiment, it is a figure which shows typically the state in which the actuator which has a hole in an arm and has a dielectric sheet adhering to an arm is located in the outermost periphery position on a magnetic disc. In this embodiment, it is sectional drawing which shows the structure of an air spoiler typically. FIG. 6 is a diagram schematically showing an actuator at a radial position on the inner peripheral side in a conventional HDD. FIG. 6 is a diagram schematically showing an actuator at a radial position on the outer peripheral side in a conventional HDD. 6 is a graph showing a change in a projected area of an actuator with respect to a magnetic disk according to a disk radius position and a change in a head-disk voltage according to a disk radius position in a conventional HDD.

  The preferred embodiments of the present invention will be described below. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. Moreover, in each drawing, the same code | symbol is attached | subjected to the same element and the duplication description is abbreviate | omitted as needed for clarification of description. In the present embodiment, a hard disk drive (HDD) will be described as an example of a disk drive.

  The HDD according to this embodiment is characterized by an actuator design. The actuator of this embodiment is designed so that a change in capacitance formed between the arm and the magnetic disk due to the radial position on the disk is small. As a result, the voltage change between the head slider and the magnetic disk is suppressed, and the probability of the head-disk discharge that causes damage to the head element portion is reduced.

  FIG. 1 is a diagram showing a schematic configuration of a hard disk drive (HDD) 100 according to the present embodiment. FIG. 1 shows a state of the HDD 100 in which the actuator is on the magnetic disk. In FIG. 1, in order to clarify the overlapping position of the actuator and the magnetic disk, the outer peripheral edge of the magnetic disk under the actuator is clearly shown. This point is the same in other drawings described below.

  In FIG. 1, the base 102 constitutes a disk enclosure by fixing a cover (not shown) that closes an upper opening of the base 102 via a gasket (not shown), and accommodates the components of the HDD 100. In the following description, the base side is referred to as the lower side, and the top cover side is referred to as the upper side. The HDD 100 has a magnetic disk 101 that is a disk for storing data. The HDD 100 has one or more magnetic disks, and FIG. 1 shows a top magnetic disk 101.

  The clamp 103 fixes the magnetic disk 101 to the spindle motor (SPM) 104. The SPM 104 is fixed to the bottom surface of the base 102 and rotates the magnetic disk 101 at a predetermined angular velocity. In FIG. 1, the magnetic disk 101 rotates counterclockwise. When the HDD 100 is not operating, the SPM 104 is stationary. The head slider 105 that accesses (reads or writes) the recording area of the magnetic disk has a slider and a head element portion formed on the slider. The head element portion generally has a read element and a write element. The present invention is applicable to an HDD having only one of a read element and a write element.

  The actuator 106 is a moving mechanism that supports the head slider 105 and moves the head slider 105 in the disk radial direction by rotating about the rotation shaft 107. The actuator 106 is coupled to a VCM (voice coil motor) 109, and the driving force of the VCM 109 rotates the actuator 106. The VCM 109 has a magnet and a coil, and the coil is fixed to the actuator 106. The actuator 106 has an arm 161 opposite to the VCM 109 across the rotation shaft 107. Furthermore, a suspension 162 is provided at the tip of the arm 161. An arm 161 exists between the suspension 162 and the rotation shaft 107.

  The actuator 109 typically has a plurality of arms and a suspension. FIG. 1 shows a top arm 161 and a top suspension 162. One suspension corresponds to the recording surface, and each suspension supports a head slider that accesses the recording surface. The top and bottom arms support suspensions corresponding to the top magnetic disk 101 and the bottom magnetic disk, and the arm between the magnetic disks supports the suspension on both sides thereof.

  The arm 161 is made of metal, and is typically made of aluminum alloy or stainless steel. The same applies to the other arms. A suspension 162 is fixed on the surface of the arm 161 on the side facing the magnetic disk 101. Similarly, the suspension 162 is also made of metal, and is typically made of stainless steel. In general, the suspension 162 is composed of a plurality of parts such as a load beam and a gimbal. In the HDD to which the present invention is applicable, the structure of the suspension is not particularly limited.

  The HDD 100 has a ramp 115 in the vicinity of the outer peripheral edge of the magnetic disk. FIG. 1 is a schematic diagram, and the ramp 115 is separated from the outer peripheral edge of the magnetic disk, but a part of the typical ramp 115 overlaps with the outer peripheral edge of the magnetic disk and the vicinity thereof. The actuator 106 stands by on the lamp 115 in the power save mode or when the power is turned off.

  When the actuator 106 is in the standby position, the head slider 105 is not on the magnetic disk 101 but outside it. In general, the suspension 162 has a tab that slides on the ramp 115. In FIG. 1, this tab is omitted. When the actuator 106 is on the ramp 115, the tab is supported by the ramp 115. The tab slides on the surface of the ramp 115 by the rotation of the actuator 106.

  The actuator 106 rotates about the rotation shaft 107, moves the head slider 105 on the recording surface of the magnetic disk 101, and further moves between the recording surface of the magnetic disk 101 and the ramp 115. As the actuator 106 rotates, the head slider 105 moves along the radial direction of the recording surface of the magnetic disk 101, and the head slider 105 can access a desired track. The pressure due to the viscosity of the air between the air bearing surface of the slider facing the magnetic disk 101 and the rotating magnetic disk 101 balances with the pressure applied to the magnetic disk 101 by the suspension 162, whereby the head slider 105. Floats on the magnetic disk 101.

  FIG. 2A shows a state where the actuator 106 is at the innermost circumferential position on the magnetic disk 101. The innermost circumferential position is the innermost circumferential position at which the actuator 106 can be mechanically positioned. Typically, the actuator 106 is in contact with the inner circumferential crash stop. At the innermost circumferential position, the head slider 105 floats on the magnetic disk 101 by its flying force. Therefore, FIG. 2A shows the innermost circumferential position in the region where the head slider 105 floats with its flying force.

  When the actuator 106 rotates to the outer peripheral side, the actuator 106 (the tab) contacts the lamp 115, and the actuator 106 moves on the ramp 115 to the outer peripheral side. FIG. 2B shows a state where the actuator 106 that rotates outwardly contacts the lamp 115. Thereafter, the actuator 106 rides on the ramp 115, and further moves to the outer peripheral side. When the actuator 106 rides on the ramp 115, the actuator 106 raises the head slider 105. Therefore, the actuator 106 shown in FIG. 2B is at the outermost peripheral position of the region in which the head slider floats on the magnetic disk 101 by its flying force.

  As can be understood by comparing FIG. 2A and FIG. 2B, when the actuator 106 is at the outermost peripheral position, a part of the arm 161 is outside the magnetic disk 101. Due to the change in the projected area of the arm 161 onto the magnetic disk 101, the capacitance between the arm 161 and the magnetic disk 101 changes. As a result, the voltage between the head slider 105 and the magnetic disk 101 (head-disk voltage) changes greatly. A decrease in the projected area results in an increase in the head-disk voltage, which increases the possibility of damage to the head element portion due to the head-disk discharge.

  2A and 2B, the arm 161 has a hole in the outer peripheral region. 2A and 2B, the arm 161 has three holes 611a to 611c. Thus, by providing the hole in the outer peripheral side region, the change in the capacitance between the arm 161 and the magnetic disk 101 due to the actuator position can be reduced, and the occurrence probability of the head-disk discharge can be reduced. .

  As shown in FIGS. 2A and 2B, the arm 161 has an inner peripheral end 612 and an outer peripheral end 613 extending in a direction connecting the rotation shaft 107 and the suspension 162. As shown in FIGS. 2A and 2B, when viewed in the disk normal direction (slider flying direction), the inner peripheral side end 612 is curved, and the outer peripheral side end 613 is linear. In the present invention, the shapes of the inner peripheral end 612 and the outer peripheral end 613 are not particularly limited.

  Generally, the outer peripheral side end 613 is linear. The suspension 162 has a tail portion (see the tail portion 621 in FIG. 3A) extending toward the rotation shaft 107, and the tail portion is fixed to the linear outer peripheral end 613. On the tail portion, 105 signal transmission lines of the head slider are laid out.

  The arm 161 has an inner peripheral region 614 and an outer peripheral region 615 between the outer peripheral end 613 and the inner peripheral end 612. The inner circumferential area 614 is an area facing the magnetic disk 101 at any position between the innermost circumferential position and the outermost circumferential position of the arm 161. That is, the inner peripheral area 614 and the magnetic disk 101 overlap each other when viewed in the disk normal direction. The outer circumferential area 615 is opposed to the magnetic disk 101 in the disk normal direction at the innermost circumferential position, is located outside the outer circumferential edge 211 of the magnetic disk at the outermost circumferential position, and is not opposed to the magnetic disk 101. It is.

  As shown in FIGS. 2A and 2B, holes 611 a to 611 c are formed in the outer peripheral side region 615. The outer peripheral side region includes regions of these holes 611a to 611c. No hole is formed in the inner peripheral region 614. For this reason, the electrostatic capacity per unit area between the outer peripheral area 615 and the magnetic disk 101 at the innermost peripheral position is larger than the electrostatic capacity per unit area between the inner peripheral area 614 and the magnetic disk. small. Thereby, the change in electrostatic capacity between the arm 161 and the magnetic disk 101 from the innermost peripheral position to the outermost peripheral position can be reduced, and the head-disk discharge can be effectively suppressed.

  In a preferred configuration, the amount of change in capacitance of the outer peripheral side region 615 between the innermost peripheral position and the outermost peripheral position is the total capacitance of the inner peripheral side region 614 and the outer peripheral side region 615 at the innermost peripheral position. It is 5% or less, more preferably 1% or less. When the capacity change from the innermost position to the outermost position is within this range, the head-disk discharge can be more effectively suppressed. This point is the same for the arm having a dielectric sheet and the arm having a hole in the outer peripheral side region and the dielectric sheet described below.

  Considering the projected area of the arm 161, the amount of change in the projected area of the outer peripheral side region 615 on the magnetic disk 101 between the innermost peripheral position and the outermost peripheral position is the same as that of the inner peripheral side region 614 at the innermost peripheral position. It is preferably 5% or less of the total projected area of the side region 615, and more preferably 1% or less. The projected area is an area of a metal portion facing the magnetic disk 101 in the arm 161. Therefore, the projected area of the outer peripheral side region 615 region at the innermost peripheral position is the area of the metal portion excluding the holes 611a to 611c from the outer peripheral side region 615 region.

  2A and 2B, the outer peripheral side region 615 includes an outer peripheral end 616 including a part of the outer peripheral end 613, three holes 611a to 611c, and beams 617 and 618. The beam 617 connects the outer peripheral end 616 and the beam 618. Since the outer peripheral area 615 has a plurality of holes instead of a single hole, a change in the projected area of the outer peripheral area 615 (area facing the magnetic disk 101 in a portion other than the holes 611a to 611c) (with the outer peripheral area 615) The decrease in the strength of the arm 161 can be reduced while reducing the change in capacitance with the magnetic disk 101. Depending on the design, there may be only one hole in the outer peripheral region 615.

  The holes 611b and 611c are on the rotating shaft side of the hole 612a, and the holes 611a and 611c are on the inner peripheral side of the hole 612b. As shown in FIG. 2A, the rotation shaft side ends of the holes 611b and 611c coincide with the magnetic disk outer peripheral end 211 in the disk normal direction at the innermost peripheral position. Thereby, the area of the metal part of the outer peripheral side region 615 can be further reduced while securing the area of the metal part of the arm 106. The hole in the outer peripheral region preferably has such a shape, but may have a shape different from these.

  Further, as shown in FIG. 2B, when the arm 161 is at the outermost peripheral position, the inner peripheral side ends (see FIG. 2A) of the holes 611a and 611c coincide with the magnetic disk outer peripheral end 211 in the disk normal direction. Yes. Thereby, the area of the metal part of the outer peripheral side region 615 can be further reduced while securing the area of the metal part of the arm 106. The hole in the outer peripheral region preferably has such a shape, but may have a shape different from these.

  Preferably, as in this configuration example, the inner peripheral region 614 does not have a hole and is formed of a continuous metal portion. Thereby, the projected area (opposite area) of the inner peripheral region 614 onto the magnetic disk 101 can be increased, and the change in capacitance between the arm 161 and the magnetic disk 101 due to the rotation of the actuator 106 is reduced. be able to. Depending on the design, the inner peripheral region 614 may have a hole.

  In order to prevent discharge between the head and the disk, it is important that the change in capacitance in the outer peripheral region is smaller than the capacitance in the outer peripheral region and the inner peripheral region. The above configuration reduces the capacity per unit area of the outer peripheral side region by forming holes in the outer peripheral side region to reduce the projected area (metal area) onto the magnetic disk 101. Thereby, the capacitance change of the outer peripheral side region with respect to the electrostatic capacitance of the outer peripheral side region and the inner peripheral side region can be reduced. In contrast to this, by making the capacitance of the unit area of the inner peripheral region larger than the capacitance per unit area of the outer peripheral region, it is possible to reduce the relative capacitance change of the outer peripheral region.

  In the HDD shown in FIGS. 3A and 3B, a dielectric sheet 301 is attached to the inner peripheral side region 614 of the arm 161. 3A shows the actuator 106 at the innermost peripheral position, and FIG. 3B shows the actuator 106 at the outermost peripheral position. The dielectric sheet 301 is attached on the magnetic disk facing surface of the arm 161. The dielectric sheet 301 increases the electrostatic capacitance between the inner peripheral region 614 and the magnetic disk 101, and increases the electrostatic capacitance per unit area of the inner peripheral region 614. Thereby, the relative capacitance change in the outer peripheral region is reduced, and the head-disk discharge is effectively suppressed.

  In the configuration of FIGS. 3A and 3B, the outer peripheral side region 615 does not have a hole unlike the configuration of FIGS. 2A and 2B, and the entire outer peripheral region 615 is formed of a continuous metal. Therefore, in the present configuration example, the difference in capacitance per unit area between the inner peripheral region 614 and the outer peripheral region 615 depends on the dielectric sheet 301.

  3A and 3B, the dielectric sheet 301 is circular, but the dielectric sheet 301 may have any shape. By covering the entire surface of the inner peripheral region 614, the capacity of the inner peripheral region 614 can be increased efficiently even with a dielectric material having a low dielectric constant. In order to increase the capacitance, it is preferable that the dielectric sheet has a high relative dielectric constant. Preferably, the relative dielectric constant of the dielectric material constituting the dielectric sheet 301 is 9 or more, more preferably 30 or more.

  In order to reduce the capacitance change of the outer peripheral side region 615, it is preferable that the dielectric sheet 301 is outside the outer peripheral side region 615 and a part of the dielectric sheet 301 is not present in the outer peripheral side region 615. A plurality of dielectric sheets may be attached to the inner peripheral region 614. Moreover, they may be composed of different dielectric materials. In any configuration, it is preferable that a dielectric sheet of the same material as the dielectric sheet attached in the inner peripheral region 614 is not attached in the outer peripheral region 615.

  3A and 3B show a top arm 161 having a dielectric sheet 301 only on the surface facing the magnetic disk 101. FIG. The arm inserted between the magnetic disks preferably has dielectric sheets on both sides. This is because both sides of the arm between the magnetic disks are opposed to the magnetic disk, and the change in capacitance can cause a head-disk discharge.

  The actuator 106 has both the shape of the outer peripheral side region 615 shown in FIGS. 2A and 2B and the dielectric sheet 301 shown in FIGS. 3A and 3B, thereby more effectively reducing the capacitance change due to the disk radial position. be able to. 4A and 4B show the actuator 106 having such a configuration. 4A shows the actuator 106 at the innermost peripheral position, and FIG. 4B shows the actuator 106 at the outermost peripheral position. The shape of the outer peripheral region 615 shown in FIGS. 4A and 4B is the same as the shape shown in FIGS. 2A and 2B. The description given with reference to FIGS. 2A and 2B and the description given with reference to FIGS. 3A and 3B can be applied to this configuration.

  By using the outer peripheral side region 615 in which the holes are formed and the dielectric sheet 301 in combination, the area of the holes or the dielectric sheet can be reduced, or a material having a low dielectric constant can be used. When forming a hole in the outer peripheral side region 615 causes a decrease in the strength of the arm 161, the dielectric sheet 301 is attached to the inner peripheral side region, thereby reducing the hole in the outer peripheral side region 615 and increasing the strength of the arm 161. Can be raised. Further, since a low dielectric constant material can be used, the usable dielectric material can be widened, and the design can be made easier.

  Next, the plate structure that suppresses the airflow caused by the rotation of the magnetic disk is described. In the HDD 100, the airflow generated by the rotation of the magnetic disk is a problem. The actuator is shaken by the airflow accompanying the rotation of the magnetic disk, and accurate positioning of the head is prevented. Therefore, in order to suppress this air flow, a technique is known in which a plate facing the magnetic disk recording surface is arranged.

  A damper plate and an air spoiler are known as parts having such a plate. These plates are placed upstream or downstream of the actuator to reduce the airflow associated with the magnetic disk rotation and improve head positioning. Generally, the damper plate is a plate having a large area, and each plate is individually fixed to the base. On the other hand, an air spoiler is generally a component in which a plate facing a disk recording surface is integrally formed, and the area of the plate is smaller than that of a damper plate.

  Since such an airflow suppression plate faces the recording surface of the magnetic disk, when it is made of metal, it forms a capacity with the magnetic disk. The increase in the capacity between the magnetic disk and the airflow suppression plate reduces the voltage between the head slider and the magnetic disk. Therefore, in a preferred configuration, the HDD 100 has an airflow suppression plate, and further, the airflow suppression plate has a metal part and a dielectric formed on the disk-facing surface of the metal part.

  FIG. 5 is a cross-sectional view schematically showing the structure of the air spoiler 51. In the configuration example of FIG. 5, the HDD has three magnetic disks 101 a to 101 c fixed to a spindle motor 104. The air spoiler 51 has four plates 511a to 511d, and the second and third plates 511b and 511c are located between the two magnetic disks. The top and bottom plates 511a and 511d face only the top and bottom magnetic disks 101a and 101c, respectively.

  The plates 511a to 511d have the same structure. The plate 511a will be described in detail. As shown in FIG. 5, the plate 511a includes an internal metal portion 512 and dielectric portions 513a and 513b formed on both upper and lower surfaces thereof. The metal part 512 is electrically connected to the base 102 via the support part of the air spoiler 51. Base 102 can be considered ground.

  The dielectric parts 513a and 513b are made of the same material as the dielectric sheet 301, for example. In this way, by having the dielectric portion between the metal portion and the magnetic disk, the capacitance between the plate 511a and the magnetic disk can be effectively increased, and thereby the head-disk space can be increased. The voltage can be reduced.

  In the example of FIG. 5, the plate 511a has the dielectric portion 513b on the top surface not facing the magnetic disk, but this may be omitted. The same applies to the bottom plate 511d. Since both the upper and lower surfaces of the plates 511b and 511c between the disks face the magnetic disk recording surface, they have dielectric portions on both disk facing surfaces. FIG. 5 shows the structure of the air spoiler plate, but a damper plate having a similar structure can also effectively reduce the head-disk voltage.

  As mentioned above, although this invention was demonstrated taking preferable embodiment as an example, this invention is not limited to said embodiment. A person skilled in the art can easily change, add, and convert each element of the above-described embodiment within the scope of the present invention. For example, the present invention is particularly useful for HDDs, but may be applied to other disk drive devices. In order to reduce the capacitance per unit area of the outer peripheral area relatively to the inner peripheral area, the average value of the distance between the outer peripheral area and the magnetic disk is calculated by You may make larger than the average value of distance between.

51 Air spoiler, 61 Actuator, 62 Ramp, 63 Magnetic disk 100 Hard disk drive, 101, 101a to 101c Magnetic disk 102 Base, 103 Clamp, 104 Spindle motor 105 Head slider, 106 Actuator, 107 Rotating shaft, 115 Lamp 161 Arm, 162 Suspension, 211 Magnetic disk outer peripheral end 301 Dielectric sheet, 511a to 511d plate, 512 Internal metal 513a, 513b Dielectric, 611a to 611c hole, 612 Inner peripheral end 613 Outer peripheral end, 614 Inner peripheral side Area, 615 Outer peripheral area, 616 Outer edge 617, 618

Claims (9)

A disk to store data,
A head slider floating above the disk;
An actuator that supports the head slider and moves the head slider in the radial direction of the disk by rotating on a rotation axis;
The actuator is
A suspension for supporting the head slider;
An arm that is between the suspension and the pivot shaft and supports the suspension and is made of metal;
The arm is
On the rotating disk, the head slider faces the disk at the innermost peripheral position of the area where the head slider is levitated by the flying force, and is outside the disk when the outermost position of the area is at the outermost position. An outer peripheral region,
An inner peripheral side of the outer peripheral side region, the inner peripheral side region facing the disk between the innermost peripheral position and the outermost peripheral position,
The electrostatic capacity per unit area between the outer peripheral side region and the disk at the innermost peripheral position is the electrostatic capacity per unit area between the inner peripheral region and the disk at the innermost peripheral position. Smaller than capacity,
Disk drive. In the inner peripheral side region, the dielectric sheet is attached to a surface facing the disc of the arm,
The disk drive of claim 1. A hole is formed in the outer peripheral side region,
The disk drive according to claim 2. It said dielectric sheet is attached only to the inner peripheral side region,
The disk drive according to claim 2. The dielectric sheet is formed of a material having a relative dielectric constant of 9 or more.
The disk drive according to claim 2. A hole is formed in the outer peripheral side region,
The disk drive of claim 1. A plurality of holes are formed in the outer peripheral side region,
The disk drive of claim 6. The amount of decrease in the capacitance of the outer peripheral side region in the movement from the innermost peripheral position to the outermost peripheral position is a region obtained by combining the inner peripheral side region and the outer peripheral side region at the innermost peripheral position, and 5% or less of the capacitance between the disk and the disk,
The disk drive of claim 1. Further comprising a plate facing the disk and suppressing airflow due to rotation of the disk;
The plate includes a metal part and a dielectric part formed on a surface of the metal part facing the disk.
The disk drive of claim 1.

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