Magnetic disk drive

Abstract

The problem that this invention aims to solve is to provide a magnetic disk device that achieves both suppression of the reduction in the positioning accuracy of the magnetic head due to flow and a reduction in the amount of particles adhering to the disk. [Solution] The magnetic disk device of the embodiment comprises a rotating shaft, a shroud, and a damper. The rotating shaft rotates a plurality of disks. The shroud surrounds at least a portion of the disks, along the outer edge of the disks, with a gap between the shroud and the outer edge of the disks. The damper is provided downstream of the shroud with respect to the flow between the disks induced by the rotation of the disks, and the damper has a portion that intersects with the flow and a portion that follows the flow.

Description

Technical Field

[0001] Embodiments of the present invention relate to a magnetic disk drive.

Background Art

[0002] As the recording density of magnetic disks increases, it becomes necessary to position the magnetic head with high precision. When the magnetic disk rotates at high speed, the speed of the gas flow inside the device increases and the turbulence also increases. When the flow is fast and the turbulence is large, the force received by the arm supporting the magnetic head increases, or vibrations occur in the arm, which contributes to a decrease in positioning accuracy. In addition, particles such as dust in the magnetic disk drive adhere to the disk surface, damaging the disk surface or causing data read / write errors.

[0003] Therefore, there is a need for a magnetic disk drive that can achieve both suppression of the decrease in the positioning accuracy of the magnetic head due to the flow and reduction of the amount of particles adhering to the disk.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem that this invention aims to solve is to provide a magnetic disk device that achieves both suppression of the reduction in the positioning accuracy of the magnetic head due to flow and a reduction in the amount of particles adhering to the disk. [Means for solving the problem]

[0006] The magnetic disk device of the embodiment comprises a rotating shaft, a shroud, and a damper. The rotating shaft rotates a plurality of disks. The shroud surrounds at least a portion of the disks, along the outer edge of the disks, with a gap between the shroud and the outer edge of the disks. The damper is provided downstream of the shroud with respect to the flow between the disks induced by the rotation of the disks, and the damper has a portion that intersects with the flow and a portion that follows the flow. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram of the inside of a magnetic disk drive in the first embodiment. [Figure 2] This is a cross-sectional view taken along the line X-Y in Figure 1. [Figure 3] This is an example of a schematic diagram of a magnetic disk drive when the disk is stopped. [Figure 4] Figure 1 is a schematic diagram with arrows indicating the airflow. [Figure 5] This graph shows the time-dependent change in the force exerted on the arm by the airflow. [Figure 6] This is a schematic diagram of the inside of the magnetic disk drive in the second embodiment. [Modes for carrying out the invention]

[0008] The following describes embodiments for carrying out the invention. The configurations and controls of the embodiments and modifications shown below, as well as the functions and effects brought about by such configurations and controls, are examples only. Furthermore, the multiple embodiments illustrated below include similar components. Hereafter, similar components are given common reference numerals, and redundant descriptions are omitted.

[0009] (First embodiment) Figure 1 is a schematic diagram of the inside of a magnetic disk drive 1 in this embodiment. The magnetic disk drive 1 has a casing 21. The casing 21 is filled with a medium gas such as air or helium. Inside the casing 21 are one or more disks 11 which are magnetic disks that serve as recording media, a shroud 10 surrounding the disks 11, a rotating shaft 12, a magnetic head 13 for recording or reproducing information on the recording media, an arm 14 that supports the magnetic head 13, a guide vane 15, a damper 17, and an actuator for controlling the position of the magnetic head. The multiple disks 11 rotate around the rotating shaft 12. The inside of the casing 21 is divided into a disk-side area 2 where the disks 11 are housed and an equipment-side area 3 where the magnetic head 13, arm 14, actuator, etc. are housed. Figure 1 illustrates the state when the disks 11 rotate counterclockwise around the rotating shaft 12 and the magnetic head 13 is positioned on the surface of the disks 11 and between the disks 11 to read and write data.

[0010] A shroud 10 is provided inside the casing 21, surrounding at least a portion of the disk 11, with a gap between it and the outer edge of the disk 11, and along the outer edge of the disk 11. In the region where the shroud 10 is along the disk 11, the gap between the shroud 10 and the disk 11 is preferably 0.1 mm or more and 1.0 mm or less.

[0011] The disk 11 is a disc-shaped recording medium, and multiple disks are stacked together. The number of disks 11 can be changed according to the specifications. The disk 11 may be a single-sided or double-sided magnetic layer, but in this embodiment, it will be described as a double-sided type. Multiple disks 11 are mounted so as to be rotatable in the rotational direction by a rotation axis and are stacked at predetermined intervals in the direction of the rotation axis. In this specification, the main surface of the disk 11 may be referred to as the "disk surface," and the disk surface may be described as including the front and back surfaces of the disk 11.

[0012] The rotating shaft 12 is the axis that rotates the disk 11. The rotating shaft 12 is connected to a drive motor (not shown), and the disk 11, which is fixed to the rotating shaft 12 and arranged to be rotatable, rotates around the rotating shaft 12 as its central axis. The rotational speed of the disk 11 when the rotating shaft 12 is driven is generally several thousand rpm to tens of thousands of rpm, but the rotational speed of the disk 11 in this embodiment is not limited to this range. In this embodiment, the counterclockwise rotation in Figure 1 is described as the direction of rotation of the disk 11.

[0013] The magnetic head 13 reads data recorded on the disk 11 and writes data to the disk 11. The magnetic head 13 is located at the tip of the arm 14. Figure 2 is a cross-sectional view taken along the line X-Y in Figure 1. The magnetic heads 13 and disks 11 are arranged alternately. The magnetic head 13 located at the top of the disk 11 can read and write (hereinafter referred to as read and write) the top surface (front) of the disk 11, the magnetic head 13 located between the disks 11 can read and write the bottom surface (back) of the disk 11 above it and the front surface of the disk 11 below it, and the magnetic head 13 located at the bottom of the disk 11 can read and write the back surface of the disk 11 above it. Figure 3 is an example of a schematic diagram of a magnetic disk drive when the disk 11 is stopped. When the rotation of the disk 11 stops, each magnetic head 13 and arm 14 is retracted from the disk 11 as shown in Figure 3. Then, when the rotating shaft 12 is driven to rotate and the disk 11 is in a rotating state, the centrifugal force and surface viscosity generate an airflow in the direction of rotation of the disk 11, causing each magnetic head 13 to float a predetermined amount (for example, about 10 nm) above the surface of the disk 11. The position of the arm 14 is then controlled by the actuator, allowing the magnetic head 13 to read and write data to the magnetic layer of the disk 11 in the portion facing the magnetic head 13. The disk 11 that the magnetic head 13 faces corresponds to the disk 11 directly above the magnetic head 13 and the disk 11 directly below the magnetic head 13. In other words, the magnetic head 13 reads and writes information to the disk 11 facing it.

[0014] The arm 14 is a member that supports the magnetic head 13. The magnetic head 13, which is located at the tip of the arm 14, is positioned so that it can enter the gaps in the stacking direction of the disk 11.

[0015] The actuator drives and controls the arm 14, and controls the position of the magnetic head 13 relative to the disk 11. The actuator is included in equipment A in Figure 1. Examples of actuators include voice coil motors and stepping motors, but the actuator in this embodiment is not limited to these.

[0016] The guide vane 15 is positioned between the disk-side region 2 and the equipment-side region 3, roughly following the disk 11, and extends from the downstream end of the shroud 10 in the direction of the rotation of the disk 11 to just before the damper 17. In other words, the guide vane 15 is provided between the downstream end of the shroud 10 in the direction of the flow between the disk 11 and the shroud 10 induced by the rotation of the disk 11, and the damper 17, roughly following the disk 11, and one end of the guide vane 15 is connected to the downstream end of the shroud 10 in the direction of the flow. The phrase "roughly following" is used here because the distance between the guide vane 15 and the disk 11 is not perfectly constant and may vary depending on the position.

[0017] As shown in Figure 1, the damper 17 is located near the base of the arm 14, upstream of the arm 14, with respect to the airflow between the disks 11 induced by the rotation of the disks 11. Here, "the airflow between the disks 11 induced by the rotation of the disks 11" is a counterclockwise airflow in the figure centered on the rotation axis 12, and near the damper 17, this airflow flows with the damper 17 side upstream and the arm 14 side downstream. The damper 17 is located downstream of the shroud 10 with respect to the airflow between the disks 11 induced by the rotation of the disks 11. The damper 17 has a comb-shaped structure that is inserted between each disk 11, similar to the arm 14. The damper 17 has a portion that intersects with the airflow between the disks 11 induced by the rotation of the disks 11 and a portion that follows the airflow. The damper 17 has a roughly L-shape, with a portion extending from the outer edge of the disc 11 toward the center (first portion: 171) and a portion extending in the opposite direction to the rotation direction of the disc 11 (second portion: 172) connected in a curved manner. In other words, the first portion 171 and the second portion 172 are smoothly continuous and have no corners. The longer the first portion 171, the greater the amount of flow 101d that can be decelerated, but this may lead to difficulties in ensuring strength and manufacturing. Therefore, theoretically, the length of the first portion 171 is not limited in order to obtain the effects of the invention, but in practice, it is preferable that the length of the first portion 171 be approximately 2 / 3 or less of the radius of the disc 11. The length of the second portion 172 is not particularly limited, but similar to the length of the first portion 171, if it is too long, practical difficulties are anticipated, so it is preferable that the length of the second portion 172 be approximately 1 / 2 to 3 / 2 of the length of the first portion 171. Furthermore, the first part 171 extends in the direction toward the axis of rotation 12. Specifically, the angle α between the first part 171 and the line connecting the point P0 (indicated as a star shape in the figure) where the first part 171 and the outer edge of the disk 11 intersect and the axis of rotation 12 is preferably 0° or more and 30° or less, and more preferably 0° or more and 10° or less. The angle β between the second part 172 and the tangent to the disk 11 at P0 is preferably 0° or more and 30° or less, and more preferably 0° or more and 10° or less. The first part 171 and the second part 172 are preferably connected by a curve.This is because, by being curvilinearly connected, it is possible to prevent the generation of a disturbed air flow caused by the separation vortex.

[0018] Hereinafter, with reference to FIG. 4, the air flow generated inside the magnetic disk device 1 will be described. The thick arrows in the figure represent the direction of the air flow in the magnetic disk device 1. Note that the positions and shapes of the thick arrows are entered for convenience of explanation, and the lengths and thicknesses of the thick arrows do not quantitatively indicate the flow velocity or flow rate of the air flow. Due to the rotation of the disk 11, an air flow is induced, and flows 101a to 101d occur near the surface of the disk 11. In this specification, the flows 101a to d may be collectively referred to as the flow 101.

[0019] Hereinafter, the air flow generated inside the magnetic disk device 1 will be described. Due to the rotation of the disk 11, an air flow is induced, and a flow 101 including flows 101a to 101d occurs in the disk side region 2 near the surface of the disk 11. Also, in the present embodiment, attention is paid to the flow 107 that is induced by the rotation of the disk 11 and passes through the gap between the disk 11 and the shroud 10. In the figure, the arrow indicating the flow 107 is entered outside the shroud 10 for the sake of visibility, but actually corresponds to the air flow flowing through the gap between the shroud 10 and the disk 11. A part of the flow 101d is decelerated by the damper 17. A part of the flow of the flow 101d is mainly blocked by the first portion 171 of the damper 17, generating a flow 102a that circulates inside the damper 17. A part of the flow 102a becomes 102c that flows downstream of the damper 17. Among the flow 101d, a part of the flow that is not blocked by the damper 17 is mainly rectified by the second portion 172 of the damper 17 and becomes the flow 102d. Since the flow 102d is rectified by the damper 17, it is a flow with less disturbance along the rotation direction of the disk 11.

[0020] The flow 102c is the air flow after passing through the space between the guide vane 15 and the second portion of the damper 17, and is decelerated by the damper 17.

[0021] The flow 107 in the gap between the shroud 10 and the disk 11 is guided by the guide vane 15 to pass through the gap in the first part 171 of the damper 17, is decelerated as it passes through the damper 17 (flow 108a), and then flows as 108b and 108c near the boundary between the disk-side region 2 and the equipment-side region 3.

[0022] Within the equipment-side region 3, there are other airflows besides flows 108a to 108c. For example, flows 115a to 115f flow around equipment A and flows 116a to 116c flow around equipment B. The diagram shows flows 115a to 115f and 116a to 116c flowing clockwise around equipment A, but the actual direction of the generated flow depends on the shape and arrangement of equipment A and B, and is not limited to the direction shown in the diagram.

[0023] In this embodiment, the arm 14 is subjected to flows 102c-d, 103, and 108a-b. However, in this embodiment, as described above, flow 102d is rectified by the damper 17 and therefore less turbulent, and flows 102c and 108a-c are decelerated by the damper 17. Therefore, the influence of these airflows on the arm 14 is reduced, and vibration of the magnetic head 13 is suppressed. Figure 5 shows the time change of the force on the arm 14 due to the airflow. The solid line shows the vibration of the magnetic head 13 when the damper 17 is provided inside the magnetic disk drive 1 (corresponding to the state in Figure 1), and the dotted line shows the vibration of the magnetic head 13 when the damper 17 is not provided inside the magnetic disk drive 1. Comparing the solid and dotted lines, it can be seen that the vibration of the magnetic head 13 is significantly reduced by providing the damper 17.

[0024] Furthermore, the less turbulent flow 102d, which is rectified by the damper 17, and the flows 102c and 108a-108c, which are decelerated by the damper 17, reduce the pressure difference between the disk-side region 2 and the equipment-side region 3, thereby reducing the amount of particles flowing from the equipment-side region 3 into the disk-side region 2.

[0025] Furthermore, in this embodiment, the flow from the disk-side region 2 to the device-side region 3 is further reduced by the guide vane 15. As a result, the flow 104 returning from the device-side region 3 to the disk-side region 2 is also reduced, which in turn reduces the inflow of particles from the device-side region 3 to the disk-side region 2, thereby reducing the amount of particles adhering to the surface of the disk 11.

[0026] Thus, according to this embodiment, the damper 17 reduces the flow deceleration and turbulence, thereby reducing the force exerted on the arm 14 and magnetic head 13 by flows 102c, 102d, and 103, and also reduces vibrations caused by the flow. As a result, by reducing the vibration of the arm 14 caused by the flow, it is possible to improve the positioning accuracy of the magnetic head 13 by the actuator, or to make positioning easier. Furthermore, conventionally, a problem was that the flow that passed through the equipment-side region 3 would carry particles with a particle size of several tens to several hundreds of nanometers present in the equipment-side region 3 and flow back into the disk-side region 2. If these particles carried to the disk-side region 2 adhere to the surface of the disk 11, it can cause various problems such as scratching the disk surface or causing errors in reading and writing data. However, according to this embodiment, the damper 17 decelerates and rectifies the flow downstream, which reduces the pressure difference between the disk-side region 2 and the equipment-side region 3. Therefore, it is possible to reduce the vibration of the arm 14 and, at the same time, reduce the intrusion of particles into the disk-side region 2.

[0027] (Second embodiment) A second embodiment is described below. Components common to the above embodiment are given the same names and reference numerals, redundant content is omitted, and the parts of this embodiment that differ from the above embodiment will be described in detail.

[0028] Figure 6 is a schematic diagram of the inside of the magnetic disk device 1 in this embodiment. The difference between this embodiment and the first embodiment is that the guide vane 15 is not provided, and a collection member 16 is provided. The collection member 16 is provided in the region between the downstream end of the guide vane 15 and the portion of the damper 17 that intersects with the flow between disks 11 induced by the rotation of the disks 11. The collection member 16 is a filter-like member that can collect fine particles such as dust carried by the flow 102b shown in the figure, which is guided by the damper 17. Note that a filter structure that can collect fine particles other than those carried by the flow from the disk side region 2 to the equipment side region 3, such as flow 102b, may be used, or the collection member 16 may be arranged so that these fine particles can be collected. For example, the collection member 16 may be able to collect fine particles carried by the flow from the equipment side region 3 to the disk side region 2.

[0029] The following describes the airflow generated inside the magnetic disk drive 1. The thick arrows in the figure indicate the direction of airflow within the magnetic disk drive 1. Note that the position and shape of the thick arrows are indicated for illustrative purposes only, and their length and thickness do not quantitatively indicate the airflow velocity or flow rate. Airflow is induced by the rotation of the disk 11, and flows 101a to 101d are generated near the surface of the disk 11. In this specification, flows 101a to 101d may be collectively referred to as flow 101.

[0030] Flow 101d is slowed down by the damper 17. When a portion of flow 101d is blocked by the damper 17, a flow 102a circulates inside the damper 17. A portion of flow 102a splits into flow 102b, which flows toward the collection member 16, and flow 102c, which flows downstream of the damper 17. Particles carried by flow 102b are collected by a filter provided in the collection member 16. Flow 102c is slowed down even more than flow 101d by the damper 17.

[0031] Of the flow 101d, a portion of the flow that was not blocked by the damper 17 is rectified by the second part 172 of the damper 17, becoming flow 102d. Because flow 102d is rectified by the damper 17, it is a smooth flow that is aligned with the rotational direction of the disc 11.

[0032] Flow 103 is the downstream flow of flows 102c and 102d. Since flow 102c is a flow decelerated by damper 17 and flow 102d is a flow straightened by damper 17, flow 103 is a decelerated flow with less turbulence. The reduced turbulence of flow 103 prevents particles near the outer edge of the disk-side region 2 from being drawn in. Furthermore, the deceleration of flow 103 increases the pressure in the region of the disk-side region 2 closer to the equipment-side region 3, mitigating the pressure difference between the disk-side region 2 and the equipment-side region 3. Consequently, the flow 104 induced by this pressure difference from the equipment-side region 3 toward the disk-side region 2 can be reduced, preventing particle-containing flows from entering the disk-side region 2.

[0033] When flow 102b passes through the collection member 16, it becomes an airflow that flows between the equipment in the equipment-side region 3. In the example shown in Figure 6, this airflow flows around equipment A, which includes actuators, etc. Let these flows be called flows 105a to 105d. In addition, there is an airflow in the equipment-side region 3 that surrounds equipment B, which is different from equipment A. Let these flows be called flows 106a to 106c.

[0034] Flow 104 includes downstream flows such as flows 106b and 106c, passes through the device-side area 3, and flows back into the disk-side area 2. Flows 108a and 108b are flows from flow 103a that are directed towards the disk-side area 2.

[0035] Thus, in this embodiment as in the first embodiment, the damper 17 reduces the flow deceleration and turbulence, thereby reducing the force on the arm 14 and magnetic head 13 from flows 102c, 102d, and 103, and also reduces vibrations caused by the flow. As a result, by reducing the vibration of the arm 14 caused by the flow, it is possible to improve the positioning accuracy of the magnetic head 13 by the actuator, or to make positioning easier. Furthermore, conventionally, a problem was that the flow that passed through the equipment-side region 3 would carry particles with a particle size of several tens to several hundreds of nanometers present in the equipment-side region 3 and flow back into the disk-side region 2. However, according to this embodiment, a portion of the flow circulates inside the damper 17, forming a flow toward the collection member 16, thereby reducing the vibration of the arm 14 and simultaneously reducing the intrusion of particles into the disk-side region 2.

[0036] By using a magnetic disk drive with the above configuration, it becomes possible to reduce the force and vibrations acting on the arm due to the flow, reduce the amount of particles adhering to the disk, and prevent scratches on the disk surface or errors during data reading and writing.

[0037] While embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. For example, the damper 17 only needs to be able to decelerate or rectify the flow, and is not limited to the damper shape shown in the first and second embodiments. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0038] Furthermore, this disclosure includes the following examples:

[0039] [Note 1] A rotating axis that rotates multiple disks, A shroud that surrounds at least a portion of the disk, with a gap between it and the outer edge of the disk, A damper is provided on the downstream side of the shroud to protect against the flow between the disks induced by the rotation of the disks, The damper has a portion that intersects with the flow and a portion that follows the flow. Magnetic disk drive.

[0040] [Note 2] When the portion of the damper that intersects with the flow is designated as the first portion, and the portion of the damper that faces from downstream to upstream of the flow is designated as the second portion, The first and second parts are connected by a curve. The magnetic disk device described in Appendix 1.

[0041] [Note 3] Guide vanes are provided along the disk between the downstream end of the shroud and the damper, in the flow between the disk and the shroud induced by the rotation of the disk, One end of the guide vane is connected to the end of the shroud. A magnetic disk device as described in Appendix 1 or 2.

[0042] [Note 4] A collection member is provided in the region between the downstream end of the shroud with respect to the flow and the portion of the damper that intersects with the flow. A magnetic disk device as described in any one of the appendices 1 to 3.

[0043] [Note 5] A magnetic head for reading data recorded on the disk and writing data to the disk, An arm having the magnetic head at its tip, An actuator for controlling the position of the head, Equipped with, The casing includes the rotating shaft, the disk, the shroud, the guide vanes, the damper, the magnetic head, the arm, and the actuator inside. A magnetic disk device as described in any one of the appendices 1 to 4. [Explanation of symbols]

[0044] 1. Magnetic disk drive 2 Disk-side area 3 Device side area 10 Shroud 11 discs 12 Rotation axes 13 Magnetic Heads 14 Arms 15 Guide vanes 16 Collection member 17 Damper 171 Part 1 172 Part 2 21 Casing A Equipment B Equipment

Claims

1. A rotating axis that rotates multiple disks, A shroud that surrounds at least a portion of the disk, with a gap between it and the outer edge of the disk, A damper is provided on the downstream side of the shroud to protect against the flow between the disks induced by the rotation of the disks, The damper has a portion that intersects with the flow and a portion that follows the flow. Magnetic disk drive.

2. When the portion of the damper that intersects with the flow is designated as the first portion, and the portion of the damper that faces from downstream to upstream of the flow is designated as the second portion, The first part and the second part are connected by a curve. The magnetic disk device according to claim 1.

3. Guide vanes are provided along the disk between the downstream end of the shroud and the damper, in the flow between the disk and the shroud induced by the rotation of the disk, One end of the guide vane is connected to the end of the shroud. The magnetic disk device according to claim 1.

4. A collection member is provided in the region between the downstream end of the shroud with respect to the flow and the portion of the damper that intersects with the flow. The magnetic disk device according to claim 1.

5. A magnetic head for reading data recorded on the disk and writing data to the disk, An arm having the magnetic head at its tip, An actuator for controlling the position of the head, Equipped with, The casing includes the rotating shaft, the disk, the shroud, the guide vanes, the damper, the magnetic head, the arm, and the actuator inside. A magnetic disk device according to any one of claims 1 to 4.

Images