disc device

Abstract

Provided is a disk device capable of reducing the occurrence rate of failures caused by contaminants. According to an embodiment, the disk device is provided with: a disk that is rotatable; an actuator that supports and drives a head; a ramp that holds the head in an unloading position; a motor that rotates the disk; and a controller that performs a loading operation of loading the head from the ramp to the disk and a seek operation of moving the head from the outer periphery to the inner periphery side of the disk after the loading. If a radial movement speed of the head at the time of the loading operation is set to Vr1, a circumferential movement speed of the head is set to Vt1, a radial movement speed of the head at the time of the seek operation is set to Vrs, and a circumferential movement speed is set to Vts, the controller controls at least one of the radial movement speed of the head and the rotational speed of the disk in such a manner as to satisfy the relationship (Vr1 / Vt1)<(Vrs / Vts).

Description

[0001] Related applications

[0002] This application enjoys priority based on Japanese Patent Application No. 2022-148072 (filed on September 16, 2022). This application incorporates the entire contents of the basic application by reference. Technical Field

[0003] Embodiments of the present invention relate to a disk device. Background Technology

[0004] As a disk device, for example, a hard disk drive (HDD) has a disk that can be rotated freely and a read / write head for recording and reading data from the disk. The read / write head has a slider (head slider) and a head disposed on the slider. During the operation of the HDD, the read / write head is positioned relative to the disk surface with a certain gap.

[0005] In HDDs, one of the main failure scenarios is damage to the read / write heads or disk when contaminants such as dust and dirt adhering to the media come into contact with them. While HDDs are maintained at a high level of cleanliness, trace amounts of dust and other contaminants are present. Therefore, a design is needed to ensure that even if these contaminants come into contact with the read / write heads, they will not cause failure. Summary of the Invention

[0006] Embodiments of the present invention provide a disk device capable of reducing the occurrence rate of failures caused by contaminants.

[0007] According to an embodiment, the disk device includes: a rotatable disk; an actuator that supports and drives a head in a manner capable of moving radially along the disk; a ramp that holds the head in an unloading position on the outer periphery of the disk; a motor that rotates the disk; and a controller that performs a loading action of loading the head onto the disk from the ramp and a seek action of moving the head from the outer periphery of the disk to the inner periphery after loading. If the radial movement speed of the head during the loading action is set to Vr1, the circumferential movement speed of the head based on the rotation of the disk is set to Vt1, the radial movement speed of the head during the seek action is set to Vrs, and the circumferential movement speed is set to Vts, then at least one of the radial movement speed of the head and the rotational speed of the disk is controlled in a manner that satisfies the relationship (Vr1 / Vt1) < (Vrs / Vts). Attached Figure Description

[0008] Figure 1 This is an exploded perspective view of the hard disk drive (HDD) according to the implementation method.

[0009] Figure 2 This is a side view showing the read / write head, suspension, and disk in the HDD.

[0010] Figure 3 This is a schematic diagram showing the HDD.

[0011] Figure 4 This is a perspective view showing the slope of the HDD.

[0012] Figure 5 This is a side view showing a portion of the slope in an enlarged manner.

[0013] Figure 6 This is a graph showing the relationship between disk rotation speed and error rate in an HDD.

[0014] Figure 7 This is a graph showing the relationship between disk rotation speed and damage rate in an HDD.

[0015] Figure 8 It is a diagram that schematically illustrates the relationship between the angle of the scratches on the recording medium and the occurrence of errors.

[0016] Figure 9 This is a graph showing the relationship between disk rotation speed and data loss rate corresponding to the width of the scratch.

[0017] Figure 10 This is a graph showing the relationship between the seek speed of the head and the data loss rate.

[0018] Figure 11 It is a diagram showing the radial and circumferential velocities during loading and seeking operations.

[0019] Figure 12 It is a graph showing the number of particles attached to the medium surface before and after the seeker.

[0020] Figure 13 It is a graph showing the relationship between the rotational speed of the disc and the height to which the head floats, based on the inner, middle, and outer circumferences of the disc.

[0021] Explanation of reference numerals in the attached figures

[0022] 10…Housing, 11…Disk drive, 17…Head, 18…Disk, 19…Spindle motor, 22…Actuator assembly, 24…Voice coil motor (VCM), 25…Ramp loading mechanism, 80…Ramp, 90…Main controller, 98A…Motor controller, 98B…VCM controller. Detailed Implementation

[0023] The following is a reference to the appendix. Figure 1 The disk device involved in the implementation method will be described below.

[0024] Furthermore, the disclosure is merely an example, and appropriate modifications that can be readily conceived by those skilled in the art to maintain the spirit of the invention are naturally included within the scope of this invention. Additionally, the drawings, in order to make the explanation clearer, sometimes schematically show the width, thickness, shape, etc., of various parts compared to the actual form, but this is always merely an example and does not limit the interpretation of the invention. Furthermore, in this specification and the various figures, the same reference numerals are used for the same elements as those described above with respect to previously presented figures, and sometimes detailed descriptions are appropriately omitted or simplified.

[0025] (Implementation Method)

[0026] As a disk device, the hard disk drive (HDD) according to the embodiments will be described in detail. Figure 1 This is an exploded perspective view of the HDD involved in the embodiment, shown with the cover removed.

[0027] like Figure 1 As shown, the HDD11 has a rectangular housing 10. The housing 10 has a rectangular box-shaped base 12 with an opening on the upper surface and a cover (top cover) 14. The base 12 has a rectangular bottom wall 12a and side walls 12b that rise along the periphery of the bottom wall, and is formed, for example, from aluminum. The cover 14 is formed, for example, from stainless steel in a rectangular plate shape. The cover 14 is threaded onto the side walls 12b of the base 12 by a plurality of screws 13, thereby hermetically sealing the upper opening of the base 12.

[0028] Multiple (e.g., 10) magnetic disks 18, which serve as disc-shaped recording media, and a spindle motor 19 that supports and rotates the magnetic disks 18 are disposed within the housing 10. The spindle motor 19 is mounted on the bottom wall 12a. Each magnetic disk 18, for example, has a substrate formed as a circular plate with a diameter of 95 mm (3.5 inches) and magnetic recording layers formed on the upper and lower surfaces of the substrate. Each magnetic disk 18 is coaxially fitted into the hub of the spindle motor 19 and clamped by a clamping spring 20. Thus, the magnetic disks 18 are supported in a position parallel to the bottom wall 12a of the base 12. The multiple magnetic disks 18 are rotated in the direction of arrow B at a predetermined rotational speed by the spindle motor 19. Furthermore, the number of magnetic disks 18 mounted is not limited to 10; it can also be 9 or less, or 10 or more but less than 12.

[0029] The housing 10 contains a plurality of magnetic heads 17 for recording and reproducing information on the disk 18, and an actuator assembly 22 that supports these magnetic heads 17 in a manner that allows them to move freely relative to the disk 18. In addition, the housing 10 contains a voice coil motor (VCM) 24 for rotating and positioning the actuator assembly 22, a ramp loading mechanism 25 for holding the magnetic heads 17 in an unloading position separated from the disk 18 when the magnetic heads 17 move to the outermost periphery of the disk 18, and a baseboard unit (FPC unit) 21 on which electronic components such as a conversion connector are mounted.

[0030] The actuator assembly 22 has an actuator block 29 supported in a manner rotatable about a support shaft 28, a plurality of arms 32 extending from the actuator block 29, and suspension assemblies 30 extending from each arm 32. The support shaft 28 is erected on the bottom wall 12a. A magnetic head 17 is supported at the top of each suspension assembly 30.

[0031] The actuator assembly 22 has a support frame (not shown) extending from the actuator block 29 in the opposite direction to the arm 32, which supports the voice coil 34. The voice coil 34 is located between a pair of yokes 37 fixed to the base 12, and together with these yokes 37 and the magnets fixed to either yoke, constitutes the VCM 24.

[0032] The FPC unit 21 has a generally rectangular base portion 21a fixed to the bottom wall 12a, an elongated strip-shaped relay portion 21b extending from one side edge of the base portion 21a, and a connecting portion 21c continuously disposed with the top end of the relay portion 21b. The base portion 21a, the relay portion 21b, and the connecting portion 21c are formed of a flexible printed wiring substrate (FPC). The connecting portion 21c is mounted on the actuator block 29.

[0033] A printed circuit board 27 is threadedly fastened to the outer surface of the bottom wall 12a of the substrate 12. The base portion 21a of the FPC unit 21 is connected to the printed circuit board 27 via a connector (not shown). The printed circuit board 27 constitutes a control unit (controller) that controls the operation of the spindle motor 19 and controls the operation of the VCM 24 and the magnetic head 17 via the board unit 21.

[0034] Figure 2 This is a side view showing the read / write head and disk in a floating state.

[0035] As shown in the figure, the disk 18 has a circular substrate 101 made of a non-magnetic material (e.g., glass). A base layer 102, a magnetic recording layer 103, and a protective film 104 are sequentially stacked on each surface of the substrate 101. The disk 18 is rotated at a predetermined speed in the direction of arrow B by a spindle motor 19.

[0036] The suspension assembly 30 includes a suspension 26, a wiring member (flexible member) 28 mounted on the suspension 26, and a tab 46 protruding from the top of the suspension 26. The magnetic head 17 is supported on the universal joint portion 41 of the wiring member 40. The magnetic head 17 is electrically connected to the aforementioned FPC unit 21 via the wiring member 40.

[0037] The read / write head 17 is configured as a floating head, having a slider 42 formed in a generally rectangular parallelepiped shape and a head 44 formed at the end of the slider 42 on the outflow (tail) side. The head 44 includes a write head element and a read head element. The read / write head 17 is maintained in a state where it is floating a predetermined amount off the surface of the disk 18 by the airflow C generated between the disk surface and the slider 42 due to the rotation of the disk 18. The direction of the airflow C is consistent with the rotation direction B of the disk 18. Accompanying the rotation of the disk 18, the read / write head 17 travels relative to the disk 18 in a direction opposite to the rotation direction B (circumferential direction).

[0038] Next, the ramp of the ramp loading mechanism 25 and the configuration relationship between the ramp and the suspension components will be explained. Figure 3 This is a three-dimensional view showing the ramp of the ramp loading mechanism. Figure 4 This is a side view showing the engagement of the top part of the suspension assembly with the ramp.

[0039] The ramp loading mechanism 25 has a ramp of 80 degrees. For example... Figure 1 As shown, ramp 80 is fixed to the bottom wall 12a of the base 12, located near the periphery of the disk 18. When the HDD is not in operation, if the read / write head 17 deviates from the outer periphery of the disk 18 and moves towards a predetermined stopping position, the tab 46 of the suspension assembly 30 climbs up ramp 80. Thus, the read / write head 17 is held in the unloaded position detached from the disk 18.

[0040] like Figure 3 As shown, the ramp 80 has a ramp body 82 formed as a rectangular plate, 10 guide blocks 84 protruding from one side of the ramp body 82, and a support bracket 85 protruding from the other side of the ramp body 82, which is integrally formed, for example, from synthetic resin or metal. By fixing the support bracket 85 to the base 12, the ramp body 82 is configured to stand upright approximately perpendicular to the bottom wall 12a of the base.

[0041] The guide block 84 has an elongated cuboid shape and extends substantially parallel to the bottom wall 12a. Ten guide blocks 84 are arranged at predetermined intervals along the axial direction of the disk 18. Figure 3 and Figure 4 As shown, a rectangular recess (notch) 86 is formed at one end of each guide block 84 on the disk 18 side. With the ramp 80 set on the base 12, the outer periphery of the 10 disks 18 is located in the recess 86 of their respective guide blocks with gaps.

[0042] Each guide block 84 has an upper guide surface (first guide surface) Ga that guides and supports the tabs 46 of the downward-facing suspension assembly 30 and a lower guide surface (second guide surface) Gb that guides and supports the tabs 46 of the upward-facing suspension assembly 30. The upper guide surface Ga and the lower guide surface Gb are opposite to each other and are arranged substantially perpendicular to one side of the ramp body 82.

[0043] The upper guide surface Ga and lower guide surface Gb of the 10 guide blocks 84 are configured to correspond to the height of the suspension components 30. Each guide surface Ga and Gb extends approximately along the radial direction of the disk 18 to the vicinity of the outer periphery of the disk 18 and is positioned on the movement path of the tab 46.

[0044] The upper guide surface Ga has a first inclined surface 87a that extends obliquely from near the surface of the disk 18 (near the recess 86) toward the direction away from the disk 18 (in this case, upward) and is used to load and unload the read / write head 17 onto the disk, a support surface 87b that extends substantially parallel to the disk surface following the first inclined surface 87a, and a second inclined surface 87c that extends obliquely from the other end of the support surface 87b to the end of the guide surface.

[0045] Similarly, the lower guide surface Gb has a first inclined surface 88a that extends obliquely from near the surface of the disk 18 (near the recess 86) toward the direction away from the disk 18 (in this case, downward) and is used to load and unload the read / write head 17 onto the disk, a support surface 88b that extends substantially parallel to the disk surface following the first inclined surface 88a, and a second inclined surface 88c that extends obliquely from the other end of the support surface 88b to the end of the guide surface.

[0046] According to HDD11, by using VCM24 to rotate actuator assembly 22 about support shaft 28, multiple read / write heads 17 move toward the desired seek position in a state opposite to the surface of each disk 18.

[0047] like Figure 4 As shown, when the HDD is not in operation, if the read / write head 17 deviates from the outer periphery of the disk 18 and moves towards a predetermined stopping position, the tabs 46 of the plurality of suspension assemblies 30 climb up the upper guide surface Ga and the lower guide surface Gb of the corresponding ramps 80, respectively, and move to the predetermined stopping position. Thus, the read / write head 17 is held in the unloaded position detached from the disk 18.

[0048] During the startup of HDD11, the actuator assembly 22 is rotated toward the disk 18 by using VCM24, and the tab 46 slides toward the disk 18 on the upper guide surface Ga and the lower guide surface Gb, and moves toward the disk 18 from the inclined surfaces 87a and 88a. As a result, the read / write head 17 is loaded onto the disk 18.

[0049] Figure 5This is a block diagram that schematically illustrates the HDD involved in the implementation.

[0050] As shown in the figure, HDD11 includes a head amplifier IC91 for driving the magnetic head 17, a main controller 90, and driver ICs 92A and 92B. The head amplifier IC91 is, for example, disposed in the actuator block of the actuator assembly 22 and electrically connected to the magnetic head 17. In this embodiment, the head amplifier IC91 and the main controller 90 constitute the controller of HDD11. The main controller 90 and driver ICs 92A and 92B are, for example, configured on a printed circuit board 27 disposed on the back side of the housing 10.

[0051] The main controller 90 includes an R / W channel 94, a hard disk controller (HDC) 96, a microprocessor (MPU) 97, a motor controller 98A, a VCM controller 98B, and a memory 93. The main controller 90 is electrically connected to the read / write head 17 via a head amplifier IC 91. The motor controller 98A is electrically connected to the spindle motor 19 via a driver IC 92A. The VCM controller 98B is electrically connected to the voice coil 34 of the VCM 24 via a driver IC 92B. The HDC 96 can be connected to a host computer 95.

[0052] The memory 93 stores data such as the moving speed (radial speed) Vr1 and circumferential speed (equivalent to disk speed) Vt1 of the read / write head during the loading action at startup, the radial speed (seeking speed) Vrs and circumferential speed (equivalent to disk speed) Vts of the read / write head during the seek action, and the seek speed Vr and circumferential speed (disk speed) Vt of the read / write head during normal operation (read and write actions).

[0053] The main controller 90's MPU97 and motor controller 98A control the rotational speed of the spindle motor 19 based on data stored in the memory 93. The MPU97 and VCM controller 98B control the radial movement speed (loading speed and seek speed) of the magnetic head 17 based on data stored in the memory 93.

[0054] Next, the loading and seeking actions of the read / write head during startup in an HDD11 configured as described above will be explained.

[0055] First, the causes of disk scratches caused by contaminants present inside the casing were verified. Figure 6 This is a graph showing the relationship between disk rotation speed and error rate in an HDD. Figure 7 This is a graph showing the relationship between disk rotation speed and damage rate in an HDD. Figure 8 It is a diagram that schematically illustrates the relationship between the angle of scratches on the recording medium and the occurrence of errors. Figure 9 This is a graph showing the relationship between disk rotation speed and data loss rate corresponding to the scratch width. Figure 10This is a graph showing the relationship between the seek speed of the head and the data loss rate.

[0056] The likelihood of damage (error rate) to a disk when the read / write head comes into contact with contaminants on the recording medium (disk) is significantly affected by the disk's rotational speed. For example... Figure 6 and Figure 7 As shown in the experimental results, the higher the disk rotation speed, the higher the disk error rate (damage rate).

[0057] This result can be considered to be based on the following: if the disk rotation speed is low, the cross-sectional speed of the medium surface during the seek operation of the read / write head is relatively increased, and the circumferential length of the damage (scars) caused by contaminants in contact with the read / write head is shorter compared with the case of high rotation speed.

[0058] like Figure 8 As shown, when the disk rotation speed is low (low circumferential speed Vt) and the head seek speed (radial speed Vr) is relatively high, the damage formed on the disk becomes a high-angle damage with a large angle relative to the circumference, and the circumferential length of the damage is short. In this case, the collapse length of the read waveform within sector 1 is short, and the probability of it becoming a read error is low.

[0059] In contrast, when the disk's rotational speed is high (high circumferential speed Vt) and the head's seek speed is relatively low (radial speed Vr), the damage formed on the disk becomes a low-angle damage, and the circumferential length of the damage increases. In this case, the collapse length of the read waveform within one sector is long, increasing the likelihood of read errors.

[0060] For example, it is known that in the case of the read channel of the HDD (4k sector drive) according to this embodiment, if the data loss caused by disk damage is less than 4.3%, it will not constitute a read error. In this HDD, with a media radius position R = 40 mm and a seek speed = 0.1 m / s, the length of one sector is approximately 500 nm. If we assume that the width of the scratch attached to the media is 100 nm, then the scratch length within one sector becomes 23 μm at a rotation speed of 5400 rpm. In this case, if... Figure 9 As shown, the data loss rate has entered the readable area of ​​less than 4.3%.

[0061] In contrast, at higher disk speeds (e.g., 7200 rpm), the scar length within a single sector becomes 30 μm. In this case, the data loss rate exceeds 4.3%, increasing the likelihood of read errors.

[0062] like Figure 9As shown, reducing disk rotation speed is more effective than reducing the width of scratches narrower than 100μm (e.g., scratches with a width of 80μm or 60μm). If the data loss rate is below 4.3%, data can still be read even if the disk is scratched, and the device will not malfunction.

[0063] When the seek speed of the read / write head changes, the data loss rate within one sector also changes. For example... Figure 10 As shown, in an HDD with a media radius R = 40mm and a disk rotation speed of 7200rpm, regardless of the scar width (100μm, 80μm, or 60μm), the data loss rate within one sector decreases by increasing the seek speed. It can be seen that if the seek speed is increased from 0.1m / s to 0.15m / s, a scar with a width of 100μm also enters the readable region. Furthermore, it can be seen that the narrower the scar width, the greater the effect.

[0064] Based on the above verification results, the data loss rate is reduced by controlling the loading speed (radial speed) and circumferential speed (equivalent to disk rotation speed) of the magnetic head during the loading action, as well as the moving speed (seeking speed) and circumferential speed (equivalent to disk rotation speed) of the magnetic head during the seek action.

[0065] Figure 11 It is a schematic diagram showing the radial and circumferential movement speeds (components) of the read / write head during loading and seeking operations.

[0066] As shown in the figure, when the radial movement speed of the read / write head 17 during the loading operation is set to Vr1, the circumferential movement speed of the read / write head based on the rotation of the disk 18 during the loading operation (when the read / write head is loaded onto the disk from ramp 80) is set to Vt1, the radial movement speed (seeking speed) of the read / write head 17 moving from the outer periphery of the disk to the inner periphery during the seek operation after loading is set to Vrs, and the circumferential movement speed of the read / write head relative to the disk is set to Vts, the main controller 90 controls the operation of the VCM24 and / or the spindle motor 19 in a manner that satisfies the relationship (Vr1 / Vt1) < (Vrs / Vts).

[0067] For example, in an HDD with a disk rotation speed of 7200 rpm during normal operation (read and write operations), if Vr1 is 0.5 m / s and Vt1 is 30 m / s during loading operations, then by setting Vrs to 1 m / s and Vts to 23 m / s during seek operations, "(Vr1 / Vt1)≈0.02<(Vrs / Vts)≈0.04". In one example, during seek operations, the main controller 90 increases the radial movement speed of the read / write head 17 from 0.5 m / s to 1 m / s and decreases the circumferential movement speed from 30 m / s to 23 m / s, for example, reducing the rotation speed of the disk 18 and the spindle motor 19 from 7200 rpm to 5400 rpm.

[0068] By controlling the radial and circumferential movement speeds of the read / write head as described above, even when the disk is scratched due to contaminants, the circumferential length of the scratches can be kept short, thus minimizing data loss. In other words, the likelihood of signal integrity degradation failures caused by scratches is reduced.

[0069] According to this embodiment, when the HDD is started, in the above-mentioned seek operation, the entire disk seek is performed by making the read / write head 17 seek from the outermost periphery to the innermost periphery of the disk 18 at least once.

[0070] Figure 12 This is a graph showing the number of particles attached to the disk surface before and after the seek operation. Figure 13 It is a graph showing the relationship between the rotational speed of the disc and the height to which the head floats, based on the inner, middle, and outer circumferences of the disc.

[0071] like Figure 12 As shown, over 90% of the contaminants adhering to the disk 18 are removed by a single full-surface seek operation of the read / write head 17. Furthermore, during the full-surface seek operation, the seek speed Vrs and circumferential travel speed Vts of the read / write head 17 are maintained at the aforementioned startup speeds: Vrs: 1 m / s and Vts: 23 m / s. That is, the disk 18 rotates at 5400 rpm. After the aforementioned full-surface seek operation, in normal data processing operations (read operations, write operations), the main controller 90 restores the disk 18's rotation speed to, for example, 7200 rpm to perform processing.

[0072] like Figure 13 As shown, even when the disk rotation speed is reduced from 7200 rpm to 5400 rpm, the head's floating posture (float height) does not change significantly. Therefore, even when performing a full-surface seek operation at a low rotation speed of 5400 rpm, the head 17 and the disk surface will not come into contact, preventing damage to the head 17 and the disk 18, and enabling the removal of contaminants.

[0073] However, the disk rotation speed cannot be set no matter how low it is. It is preferable to set the rotation speed by taking into account the floating characteristics and deviation of the read / write head.

[0074] According to the HDD of this embodiment, configured as described above, after the read / write head is loaded onto the disk surface, the disk rotation speed is reduced to a low-rotation state, and the read / write head performs a full-surface seek from the outer periphery to the inner periphery of the disk. Alternatively, by increasing the seek speed of the read / write head to perform a full-surface seek from the outer periphery to the inner periphery of the disk, contaminants adhering to the disk can be removed safely and efficiently. Furthermore, during HDD startup, by setting the relationship between the loading speed and the seek speed to (Vr1 / Vt1) < (Vrs / Vts), the traversing speed of the read / write head is increased from the perspective of the medium. Therefore, even if scratches are caused on the disk due to contact between contaminants and the read / write head, the scratches can be angled relative to the circumferential direction, resulting in a shorter circumferential signal degradation distance. Thus, contaminants on the disk can be removed while reducing the data loss rate and the possibility of read errors.

[0075] Based on the above description and this embodiment, a disc device capable of reducing the occurrence rate of malfunctions caused by contaminants can be obtained.

[0076] Furthermore, in the above embodiment, a structure is designed to increase the seek speed Vrs of the read / write head and decrease the circumferential movement speed (disk rotation speed) Vts during the seek operation at startup. However, this is not a limitation; a structure that controls only one aspect can also be configured. That is, by performing either increasing the seek speed Vrs or decreasing the circumferential movement speed (disk rotation speed) Vts, the relationship (Vr1 / Vt1) < (Vrs / Vts) can be achieved.

[0077] This invention is not limited to the embodiments described above. During implementation, the constituent elements can be modified and embodied by variations without departing from its spirit. Furthermore, various inventions can be formed through appropriate combinations of the multiple constituent elements disclosed in the above embodiments. For example, some constituent elements may be deleted from all the constituent elements shown in the embodiments. Moreover, constituent elements from different embodiments can be appropriately combined.

[0078] For example, in a disk drive, the number of disks and the number of read / write heads can be increased or decreased as needed, and the disk size can be selected from various sizes. The head movement speeds Vr1, Vt1, Vrs, and Vts are not limited to the speeds described in the above-described embodiments and can be adjusted to other speeds as appropriate.

Claims

1. A disk device comprising: A freely rotating disk; An actuator that supports and drives the head in a manner that allows it to move radially along the disk; A ramp holds the head in an unloading position on the outer periphery of the disk; A motor rotates the disk; and The controller executes a loading action of loading the head onto the disk from the ramp and a seek action of moving the head from the outer periphery to the inner periphery of the disk after loading. If the radial movement speed of the head during the loading action is set to Vr1, the circumferential movement speed of the head based on the rotation of the disk during the loading action is set to Vt1, the radial movement speed of the head during the seek action is set to Vrs, and the circumferential movement speed of the head based on the rotation of the disk during the seek action is set to Vts, then at least one of the radial movement speed of the head and the rotation speed of the disk is controlled in such a way that the circumferential movement speed Vts of the head during the seek action is set to a speed slower than the circumferential movement speed Vt1 of the head during the loading action, thereby satisfying the relationship (Vr1 / Vt1) < (Vrs / Vts).

2. The disk device according to claim 1, The controller reduces the motor's rotational speed to slow down the circumferential movement speed Vts.

3. The disk device according to claim 1, The controller sets the radial movement speed Vrs of the head during the seek operation to be faster than the radial movement speed Vr1 of the head during the loading operation, thereby satisfying the relationship (Vr1 / Vt1) < (Vrs / Vts).

4. The disk device according to claim 1, During the seek operation, the controller enables the head to perform a full-surface seek from the outer periphery to the inner periphery of the disk when the state of (Vr1 / Vt1) < (Vrs / Vts) is satisfied.

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