Suspension for disk drive

Abstract

To provide a suspension capable of suppressing interference between a disk and a slider.SOLUTION: The suspension 10 is provided with a load beam 20 having a dimple part 50 and a flexure 21 having a slider mounting part 30. The convex surface 51 of the dimple portion 50 contacts the slider mounting portion 30. The curvature radius R of the convex surface 51 is less than 0. 10mm, and the gain defined by the following equation is 0.9 or more. Where a is the input amplitude, A is the amplitude, R is the radius of curvature of the convex surface 51, and Fpr is the flexure pitching resistance. k1 is the pitching rigidity of the air bearing, and k2 is the pitching rigidity of the slider mounting portion 30.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a suspension for a disk drive having a swingable slider mounting portion on which a slider is mounted. [Background technology]

[0002] Hard disk drives (HDDs) are used in information processing devices such as personal computers. Hard disk drives include a magnetic disk that rotates around a spindle and a carriage that rotates around a pivot shaft. The carriage has an arm that rotates around the pivot shaft using a positioning motor such as a voice coil motor.

[0003] A suspension for a disk drive (hereinafter referred to as the suspension) is attached to the arm of the carriage. The suspension includes a load beam and a flexure disposed along the load beam. A slider is mounted on a slider mounting portion formed near the tip of the flexure. In the industry, the slider mounting portion is sometimes called a tongue. The slider moves integrally with the slider mounting portion in at least the pitching direction. For this reason, in this specification, the pitch angle of the slider mounting portion is sometimes referred to as the pitch angle of the slider.

[0004] The load beam, flexure, slider, etc. constitute a gimbal assembly. The slider is provided with an element for accessing the disk, such as reading or writing data. When the disk drive is in use, the slider element accesses data on the recording surface of the disk while the disk is rotating.

[0005] For example, as described in Patent Documents 1 and 2, in a suspension having a slider mounting portion, the convex surface of a dimple contacts the slider mounting portion. The dimple is provided on a load beam. The slider mounting portion is elastically supported by gimbal components such as outriggers and swings around the convex surface of the dimple. The slider is fixed to the slider mounting portion by adhesive or the like. In this specification, the slider mounting portion refers not only to the area where the slider is bonded but also to the surrounding area. In other words, the slider mounting portion refers to the entire swingable area elastically supported by the gimbal components.

[0006] As the disk rotates, air flows between the leading end of the slider and the trailing end of the slider, forming an air bearing. As used herein, "leading side" refers to the side where air flows between the slider and the disk as the disk rotates. "Trailing side" refers to the side where air flows out.

[0007] To accommodate the trend toward higher recording densities on disks, the distance between the slider and the disk tends to decrease. When the disk is rotating and the air bearing is formed, the distance between the leading edge of the slider and the disk is, for example, 100 nm. In contrast, the distance between the trailing edge and the disk is, for example, 10 nm.

[0008] Although the recording surface of a disk appears flat, in reality, there may be waviness of around several microns in amplitude around the disk's circumference. When the inventors carefully examined the flatness of the disk, they found that the waviness around the outer periphery of the disk tends to be larger than the waviness around the center clamp area near the disk's rotation center. The slider needs to move in the pitching direction to follow the waviness of the disk.

[0009] The slider swings relative to the load beam, with the convex surface of the dimple as a fulcrum. In this specification, the movement of the leading portion of the slider toward or away from the load beam in the longitudinal direction of the suspension is referred to as "pitching." The pitch angle is the angle in the pitching direction from the reference position. In this specification, movement of the leading portion of the slider toward the load beam is referred to as movement in the direction of a positive pitch angle. Movement of the leading portion of the slider away from the load beam is referred to as movement in the direction of a negative pitch angle.

[0010] When the slider moves toward the peak of a disk waviness, it moves along the disk surface in the negative pitch direction. When the slider moves toward the valley of a disk waviness, it moves along the disk surface in the positive pitch direction.

[0011] The slider is tilted at a slight positive pitch angle relative to the disk surface. This pitch angle is typically very small, e.g., 0.006°. If the waviness amplitude is, e.g., 3 to 6 μm, the slider must move in the pitching direction by a fairly large angle, e.g., ±0.03 to ±0.06°.

[0012] With the evolution of disk drives, there has been a recent trend toward shorter suspension lengths. The load beam forms a certain angle in the pitching direction with respect to the disk surface. The slider mounting section, located at the tip of the load beam, moves in the pitching direction relative to the load beam, centered on the dimple section. The shorter the suspension length, the greater the change in the slider's angle in the pitching direction. For example, it is known that when the suspension length approaches 6 mm, the slider angle change is significant. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-22013 [Patent Document 2] Japanese Patent Application Publication No. 2020-140749 Summary of the Invention [Problem to be solved by the invention]

[0014] If the slider cannot follow the waviness of the disk quickly enough, it may get too close to the disk surface, causing hot spots due to friction between the slider, the disk, or the air bearing. In extreme cases, the slider may even come into contact with the disk, potentially causing scratches on the disk or slider.

[0015] Through extensive research, the inventors have found that the slider approaches the disk excessively at locations where the pitch angle changes significantly, such as near the peaks and troughs of disk undulations. They have discovered that the gain value relative to the input amplitude is important in order to avoid interference between the disk and slider. Gain will be explained in more detail later.

[0016] In the industry, it has been customary to consider that a slider mounting portion such as a tongue oscillates while being in contact with the convex surface of the dimple at a single point. The contact between the convex surface of the dimple and the slider mounting portion is equivalent to the contact between a spherical surface rolling on a flat surface and a flat surface, and has therefore been considered to be Hertzian elastic contact. In Hertzian elastic contact, friction between the slider mounting portion (flat surface) and the convex surface of the dimple (spherical surface) can be substantially ignored. For this reason, it was not considered that the movement of the slider mounting portion would be affected by friction with the convex surface.

[0017] An object of one embodiment of the present invention is to provide a suspension for a disk drive that can suppress interference between a rotating disk and a slider. [Means for solving the problem]

[0018] As a result of intensive research, the inventors discovered that a force similar to friction in the opposite direction to the pitching direction occurs at the contact point between the convex surface of the dimple and the slider mounting part. The inventors named this force flexure pitching resistance (Fpr). Fpr is an abbreviation for Flexure Pitching Resistance. Flexure pitching resistance (Fpr) occurs at the contact point between the slider mounting part and the convex surface when the slider mounting part oscillates on the convex surface of the dimple.

[0019] A suspension according to one embodiment includes a load beam having a dimpled portion and a flexure disposed along the load beam and having a slider mounting portion for mounting a slider. The slider mounting portion has a first surface facing the load beam and a second surface to which the slider is fixed by adhesive or the like. The convex surface of the dimpled portion contacts the first surface of the slider mounting portion at a contact portion. The slider mounting portion is supported by a gimbal component so as to be able to swing at least in the pitching direction. The suspension of this embodiment is effective in avoiding interference between the disk and the slider by setting the gain to 0.9 or more. The definition of gain will be explained in detail later. A gain of 0.95 or more is even more effective in avoiding interference between the disk and the slider.

[0020] It was also found that the radius of curvature of the convex surface and the flexure pitching resistance (Fpr) affect the gain. In this embodiment, the radius of curvature of the convex surface is less than 0.10 mm and 0.04 mm or more. More preferably, the radius of curvature of the convex surface is less than 0.85 mm. The flexure pitching resistance (Frp) is 0.005 N or less. [Effects of the Invention]

[0021] The suspension of the present invention can prevent the slider, which moves in the pitching direction following the undulation of the rotating disk, from interfering with the disk. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a plan view of a portion of a suspension according to one embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a part of the suspension and the slider taken along line F2-F2 in FIG. 1. [Figure 3] FIG. 1 is a cross-sectional view schematically showing an example of a disk device. [Figure 4] FIG. 3 is a side view showing a schematic representation of a part of the suspension, a slider, and a part of the disk shown in FIG. 2; [Figure 5] FIG. 5 is a side view schematically illustrating a state in which the slider shown in FIG. 4 has moved in the direction of a negative pitch angle. [Figure 6] FIG. 5 is a side view schematically illustrating a state in which the slider shown in FIG. 4 has moved in the direction of a positive pitch angle. [Figure 7] FIG. 5 is a schematic diagram showing the motion system of the suspension, slider, and disk shown in FIG. 4. [Figure 8] 1 is a diagram showing the calculated relationship between the slider pitch angle and the disk rotation angle. [Figure 9] 1 is a diagram showing the relationship between the actual slider pitch angle and the disk rotation angle. [Figure 10] 1 is a diagram showing a schematic representation of the relationship between the disk profile and the slider pitch angle; [Figure 11] FIG. 10 is a graph showing the relationship between the disk pitch angle and the slider pitch angle when the gain is 0.701. [Figure 12] 10 is a graph showing the relationship between the disk pitch angle and the slider pitch angle for an example where the gain is 0.934. [Figure 13] 10 is a graph showing the relationship between the disk pitch angle and the slider pitch angle when the gain is 0.105. [Figure 14] FIG. 1 shows the gains of samples No. 1-17. [Figure 15] FIG. 10 is a graph showing the relationship between flexure pitching resistance Fpr and gain. [Figure 16] A graph showing the relationship between the radius of curvature R of the convex surface and the gain. DETAILED DESCRIPTION OF THE INVENTION

[0023] A suspension for a disk drive according to one embodiment will be described below with reference to the drawings. Hereinafter, the suspension for a disk drive may be simply referred to as a suspension.

[0024] FIG. 1 is a plan view showing a portion of suspension 10. FIG. 2 is a cross-sectional view of a portion of suspension 10 taken along line F2-F2 in FIG. 1. FIG. 3 is a cross-sectional view showing a schematic example of a disk device 11 having suspension 10. Disk device 11 has one or more disks 12. Disk device 11 will be described later, and suspension 10 will be described first.

[0025] The suspension 10 includes a load beam 20 and a flexure 21 disposed along the load beam 20. The load beam 20 is made of a stainless steel plate and extends in the longitudinal direction of the suspension 10. The direction indicated by the double-headed arrow X1 in FIG. 1 is the longitudinal direction of the load beam 20, i.e., the longitudinal direction of the suspension 10. The thickness of the load beam 20 is, for example, 20 to 40 μm, but may be other thicknesses.

[0026] The flexure 21 includes a metal base 22 made of a thin stainless steel plate and a wiring portion 23 arranged along the metal base 22. The thickness of the metal base 22 is, for example, 20 μm (12 to 25 μm). The thickness of the metal base 22 is smaller than the thickness of the load beam 20.

[0027] 1, the metal base 22 is fixed to the load beam 20 by a plurality of welds (for example, a first weld W1 and a second weld W2). The wiring portion 23 includes an insulating base layer made of an electrically insulating resin such as polyimide, a plurality of conductors formed on the insulating base layer, and a cover layer that covers the conductors.

[0028] A slider mounting portion 30 is formed on a part of the metal base 22. In the industry, the slider mounting portion 30 is sometimes referred to as a tongue. As shown in FIG. 2, the slider mounting portion 30 has a first surface 30a and a second surface 30b. The first surface 30a faces the load beam 20. The second surface 30b is on the opposite side of the first surface 30a in the thickness direction of the metal base 22. A slider 31 is fixed to the second surface 30b by a fixing means such as adhesive.

[0029] The slider 31 is mounted on the second surface 30b of the slider mounting portion 30 with the wiring portion 23 sandwiched therebetween. A portion of the slider 31 is fixed to the slider mounting portion 30 with an adhesive. The slider 31 has a leading side portion 31a and a trailing side portion 31b in relation to the rotation direction of the disk 12. In this specification, the "leading side" refers to the side from which air flows in between the disk 12 and the slider 31 when the disk is rotating. The "trailing side" refers to the side from which air flows out.

[0030] A plurality of elements 33 capable of converting magnetic signals to electric signals, such as MR elements, are provided at the tip 32 on the trailing side of the slider 31. These elements 33 are used to access the recording surface of the disk 12, such as to write or read data. A heater 34 may be disposed near the elements 33. When power is applied to the heater 34, the trailing side portion 31b is heated and expands. This allows the distance h1 (shown in FIGS. 4 to 6) between the trailing side portion 31b and the disk 12 to be further reduced. For example, the distance h1 can be reduced to 1 nm or less.

[0031] The distance h1 between the trailing-side portion 31b of the slider 31 and the disk 12 is sometimes referred to as head-media spacing (HMS). The distance h1 is smaller than the distance h2 between the leading-side portion 31a and the disk 12. h2 is, for example, 100 nm, while h1 is, for example, 10 nm.

[0032] 1, the slider mounting portion 30 is elastically supported on the load beam 20 by first arms 41 and 42 and second arms 43 and 44 that serve as a gimbal component 40. The first arms 41 and 42 and the second arms 43 and 44 are part of the metal base 22. The gimbal component 40 varies depending on the design of the flexure 21, and is not limited to the example shown in FIG.

[0033] A gimbal portion 45 is formed in a part of the flexure 21 by the slider mounting portion 30, the gimbal component 40, etc. The slider mounting portion 30 is a swingable portion elastically supported by the gimbal component 40. The slider mounting portion 30 includes the portion where the slider 31 is adhered and its surroundings. Actuator elements 46, 47 may be disposed on both sides of the slider 31. The actuator elements 46, 47 are made of a piezoelectric material such as PZT (lead zirconate titanate), and can slightly rotate the trailing side portion 31b of the slider 31 in the width direction when a voltage is applied.

[0034] The tip ends of the first arms 41 and 42 are supported on the load beam 20 by a first weld W1. The bases 43a and 44a of the second arms 43 and 44 are fixed to the load beam 20 by a second weld W2. That is, the slider mounting portion 30 is supported by the gimbal component 40 so as to be able to elastically swing relative to the load beam 20.

[0035] Limiter members 48, 49 may be provided between the slider mounting portion 30 and the tip end 21a of the flexure 21. The limiter members 48, 49 are made of a resin such as polyimide, and suppress excessive vibration of the slider mounting portion 30 when an external impact is applied to the suspension 10. Depending on the design of the flexure 21, the limiter members 48, 49 may function as part of the gimbal component 40.

[0036] A dimple portion 50 is formed on the load beam 20. As shown in FIG. 2, the dimple portion 50 has a convex surface 51 that protrudes in a dome shape toward the slider mounting portion 30. The convex surface 51 has a shape obtained by rotating an arc of a radius of curvature R around a vertical axis Y, and is substantially circular in a plan view of the slider mounting portion 30. The arc of a radius of curvature R is not necessarily a perfect circle. In other words, the convex surface 51 has a shape similar to a part of a hemisphere. The tip of the convex surface 51 is in contact with the first surface 30a of the slider mounting portion 30. The radius of curvature R is the radius of curvature of a portion that may come into contact with the first surface 30a when the slider mounting portion 30 swings. Other portions, i.e., portions that are not likely to come into contact with the first surface 30a, may have a radius of curvature other than R.

[0037] 2, when the convex surface 51 of the dimple portion 50 is in contact with the slider mounting portion 30, the slider mounting portion 30 swings at least in the pitching direction (the direction indicated by the double-headed arrow P in FIG. 2). As a result, the slider mounting portion 30 generates at least a vertical displacement around the convex surface 51. The slider mounting portion 30 is supported by gimbal components 40, such as outriggers and arms, so as to be swingable relative to the load beam 20 at least in the pitching direction (vertical swing direction) and the rolling direction (horizontal swing direction).

[0038] 3 is a cross-sectional view showing a schematic example of a disk drive (HDD) 11. The disk drive 11 includes a disk 12 that rotates around a spindle, a case 70 (only a portion of which is shown), a carriage 72 that can rotate around a pivot shaft 71, and a positioning motor 73 that drives the carriage 72. The case 70 is sealed with a lid. A suspension 10 is attached to the tip of an arm portion 74 of the carriage 72.

[0039] When the carriage 72 is rotated by the positioning motor 73, the suspension 10 moves in the radial direction of the disk 12, and the slider 31 moves to a desired position on the disk 12. When the disk 12 rotates, air flows from the leading side portion 31a to the trailing side portion 31b of the slider 31, forming an air bearing 80 between the disk 12 and the slider 31.

[0040] 4 schematically shows the surface 12a of the disk 12, the slider 31, and the dimple portion 50 along a flat reference plane N. The reference plane N is an imaginary flat surface extending in a direction perpendicular to the central axis of the rotating disk 12. The slider mounting portion 30 is in contact with the convex surface 51 while being elastically supported by the gimbal component 40. Therefore, the slider mounting portion 30 and the convex surface 51 come into contact with each other at a contact portion 90.

[0041] The slider mounting portion 30 moves around the center of curvature Z1 in a rolling manner on the convex surface 51 while in contact with the convex surface 51 at the contact portion 90. At this time, the convex surface 51 and the slider mounting portion 30 are in elastic contact between a flat surface and a spherical surface (Hertzian elastic contact). Therefore, there is no slippage at the contact portion, and loss due to friction is considered to be essentially negligible.

[0042] However, in reality, a force similar to friction acts at the contact portion 90 between the slider mounting portion 30 and the convex surface 51. This force is the flexure pitching resistance Fpr discovered by the inventors. The flexure pitching resistance Fpr can be determined by analysis according to the design of the flexure 21 (mainly the design of the gimbal portion 45).

[0043] FIG. 5 schematically shows the slider 31 moving on the surface 12a at a negative pitch angle θ1 relative to the reference plane N. As shown in FIG. 5, when the slider 31 moves on the surface 12a at the negative pitch angle θ1, the contact portion 90 moves in a first direction P1 from the reference line Y1. The slider mount 30 rolls on the surface of the convex surface 51 without substantially slipping. At this time, a flexure pitching resistance Fpr acts on the contact portion 90 in the tangential direction of the convex surface 51, in the opposite direction to the movement of the slider mount 30. The slider 31 is disposed on the slider mount 30. For this reason, in this specification, the pitch angle of the slider 31 and the pitch angle of the slider mount 30 are synonymous.

[0044] The flexure pitching resistance Fpr acts on the contact portion 90 as a moment of the curvature radius R. Therefore, a torque around the center of curvature Z1, expressed as the product of the flexure pitching resistance Fpr and the curvature radius R (Fpr × R), acts on the slider mounting portion 30. This torque increases as the curvature radius R increases, and provides resistance to the movement of the slider mounting portion 30 in the pitching direction.

[0045] 6 shows a schematic representation of the slider 31 moving on the surface 12a at a positive pitch angle θ2 relative to the reference plane N. As shown in FIG. 6, when the slider 31 moves on the surface 12a at the positive pitch angle θ2, the contact portion 90 moves in a second direction P2 from the reference line Y1. The slider mount 30 rolls on the convex surface 51 without substantially slipping. At this time, a flexure pitching resistance Fpr acts on the contact portion 90 in the tangential direction of the convex surface 51 in the direction opposite to the direction in which the slider mount 30 moves.

[0046] FIG. 7 is a schematic diagram of a motion system including the slider 31. In FIG. 7 and the equations thereafter, k1 is the pitch stiffness (pitch stiffness [Nm / rad]) of the slider surface 31c facing the air bearing 80. k2 is the pitch stiffness (pitch stiffness [Nm / rad]) of the gimbal portion 45 of the flexure 21. c is the viscous damping coefficient of the slider surface 31c facing the air bearing 80 and the gimbal portion 45. ζ is the viscous damping ratio. θ is the slider pitch angle [rad], a is the input amplitude [rad], Fpr is the flexure pitching resistance [N], R is the radius of curvature R [m] of the convex surface of the dimple, and ω is the circular frequency [rad / s]. I is the inertia of the slider 31 including the slider mounting portion 30, but to simplify the calculations, only the inertia of the slider 31 is considered.

[0047] Since the resistance torque Fpr × R acts in the opposite direction to the direction of rotation, the equation of motion for one degree of freedom is given by the following equations (1) and (2).

[0048]

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[0049] By transforming equations (1) and (2), the following equations (3) and (4) are obtained.

[0050]

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[0051] Equations (3) and (4) are linear and the principle of superposition holds. Therefore, the steady-state vibration solution is assumed to be the following equation (5).

[0052]

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[0053]

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[0054] Comparing the left and right sides,

[0055]

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[0056] From the above equation, U, V, and C are calculated as follows:

[0057]

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[0058]

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[0059] The steady-state solution θp was obtained from equations (6)-(9).

[0060]

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[0061] When the resistance torque Fpr is zero, the amplitude A and the phase δ are expressed by the following equations.

[0062]

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[0063] When Fpr is 0(N) and the sign of the constant term C does not change, the disk pitch angle and the slider pitch angle will match. However, when the resistance torque Fpr exists and the sign of the constant term C changes, the disk pitch angle and the slider pitch angle will not match.

[0064] Figure 8 shows the relationship between the disk rotation angle and the calculated slider pitch angle when Fpr is 0.01 N. In Figure 8, when the disk rotation angle is between 0° and 90°, the constant term C is negative, so the slider pitch angle is smaller than the disk pitch angle by that amount.

[0065] In Figure 8, when the disk rotation angle exceeds 90°, the constant term C changes to a positive value. Therefore, in calculations, the slider pitch angle increases discontinuously at 90° and becomes larger than the disk pitch angle. When the disk rotation angle exceeds 270°, the constant term C changes to a negative value. Therefore, in calculations, the slider pitch angle decreases discontinuously at 270°. From 270° to 450°, the slider pitch angle changes with a lag relative to changes in the disk pitch angle.

[0066]

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[0067] Therefore, within the range of θ, the slider pitch angle increases or decreases by a certain angle C. The slider pitch angle changes as shown in FIG. 9. This phenomenon will be explained below with reference to FIGS. 9 and 10. Note that the slider pitch angle and the pitch angle of the slider mounting portion are equal. In this specification, the pitch angle of the slider mounting portion may be referred to as the slider pitch angle.

[0068] Figure 10 shows a schematic diagram of the relationship between the profile of the surface of the disk 12 along the direction of rotation and the pitch angle of the slider. The solid line L1 in Figure 10 shows the disk profile. The dashed line L2 in Figure 10 shows the slider moving along the surface of the disk 12 when C=0.

[0069] As shown in Figures 9 and 10, when the disk rotation angle is between 0° and 90°, the disk pitch angle is positive. This causes the disk pitch angle to increase, causing the slider to rotate in the positive pitch direction and Fpr to become negative. Therefore, as shown by the solid line S1 in Figure 10, the slider pitch angle changes in the positive pitch direction with a delay relative to the change in the disk pitch angle due to the resistance of Fpr.

[0070] When the disk rotation angle exceeds 90°, the disk pitch angle decreases (negative pitch direction), causing Fpr to change from negative to positive. Therefore, when the disk rotation angle exceeds 90°, a force in the positive pitch direction is applied to the slider due to the positive Fpr, as shown by the two-dot chain line S2 in Figure 10.

[0071] However, when the disk rotation angle exceeds 90°, the disk pitch angle changes in the negative direction. Therefore, even if a positive Fpr is acting, the slider is prevented from rotating in the positive direction. Therefore, as the disk rotation angle passes 90° and then 180°, the slider pitch angle θp remains almost constant, as shown by the hatched area S3 in Figure 10.

[0072] When the disk rotation angle exceeds 180°, the disk pitch angle becomes negative and the absolute value of the pitch angle increases. Since Fpr is positive at this time, the resistance of Fpr acts to decrease the slider pitch angle. Therefore, as shown by S4 in Figure 10, the slider pitch angle changes with a lag relative to the disk pitch angle until the disk rotation angle approaches 270°.

[0073] When the disk rotation angle exceeds 270°, the disk pitch angle changes in the positive direction, causing Fpr to change from positive to negative. Therefore, when the disk rotation angle exceeds 270°, a negative Fpr applies a negative pitch force to the slider.

[0074] However, when the disk rotation angle exceeds 270°, the disk pitch angle changes to the positive pitch direction. Therefore, even if a negative Fpr is applied, the slider is prevented from rotating in the negative pitch direction. Therefore, the slider pitch angle remains constant from 270° to 360°. When the disk rotation angle exceeds 360°, the same phenomenon as described above from 0° to 360° is repeated.

[0075] 9, when the input amplitude is a, the gain is expressed by the following equation. A is the amplitude, R is the radius of curvature of the convex surface 51, and Fpr is the flexure pitching resistance. k1 is the pitching stiffness of the air bearing, and k2 is the pitching stiffness of the slider mounting portion 30.

[0076]

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[0077] Figure 11 shows the relationship between the disk pitch angle and the slider pitch angle when the gain is 0.701. In the example shown in Figure 11, the difference between the disk pitch angle and the slider pitch angle is large, so there is a possibility that the slider will interfere with the disk.

[0078] Figure 12 shows the relationship between the disk pitch angle and the slider pitch angle when the gain is 0.934. In the example shown in Figure 12, the difference between the disk pitch angle and the slider pitch angle is small, so interference between the slider and disk is unlikely to occur.

[0079] Figure 13 shows the relationship between the disk pitch angle and the slider pitch angle when the gain is 0.105. In the example shown in Figure 13, the discrepancy between the disk pitch angle and the slider pitch angle is quite large, so there is a high possibility that the slider will interfere with the disk.

[0080] Figure 14 shows the gain of each suspension sample No. 1-17. Samples No. 1 to No. 9 had small gains, which caused the slider to interfere with the disk and were deemed problematic (NG). Samples No. 10 to No. 17 prevented the slider from interfering with the disk. To prevent interference between the disk and slider, a gain of 0.9 or higher is required, and 9.5 or higher is more desirable.

[0081] Figure 15 shows the relationship between the flexure pitching resistance Fpr and the gain. The flexure pitching resistance Fpr affects the gain. The smaller the Fpr, the greater the gain. In particular, when Fpr is less than 0.005 N, the gain approaches the desired value. Figure 16 shows the results of an analysis of the relationship between the dimple curvature radius R and the gain when Fpr is 0.005 N. When the dimple curvature radius R is less than 0.1, the gain can approach 0.9. In particular, when the curvature radius R is less than 0.085, the gain can be made 0.9 or greater.

[0082] As a result of intensive research by the inventors, it was found that a gain of 0.9 or more, preferably 0.95 or more, is effective in suppressing interference between the slider and the disk. To achieve a gain of 0.9 or more, the flexure pitching resistance Fpr should be set to 0.005 N or less, and the radius of curvature R of the convex surface should be set to less than 0.10 mm, preferably less than 0.085 mm.

[0083] Due to limitations of the mold used to form the dimple portion 50, it is practically difficult to make the radius of curvature R smaller than 0.04 mm. Therefore, the radius of curvature R is set to 0.04 mm or greater. The height h3 of the dimple portion (shown in FIG. 4) is, for example, 0.04 mm to 0.07 mm, but may be any other height.

[0084] In implementing the present invention, it goes without saying that various modifications can be made to the components that make up the suspension, including specific aspects such as the load beam, flexure, slider, and shape and position of the dimples. The disk drive is also not limited to the above embodiment and can take various forms as needed. [Explanation of symbols]

[0085] 10...suspension, 11...disk device, 12...disk, 20...load beam, 21...flexure, 22...metal base, 30...slider mounting portion, 31...slider, 31a...leading side portion, 31b...trailing side portion, 40...gimbal component, 45...gimbal portion, 50...dimple portion, 51...convex surface, 80...air bearing, 90...contact portion, R...radius of curvature, Z1...center of curvature, Fpr...flexure pitching resistance.

Claims

1. A load beam, a flexure disposed along the load beam and having a slider mounting portion for mounting a slider, the slider mounting portion including a first surface facing the load beam and a second surface on which the slider is provided; A suspension for a disk drive, comprising: a dimple portion formed on the load beam and having a convex surface in contact with the first surface of the slider mounting portion; a gimbal component that supports the slider mounting portion so that the slider mounting portion can swing in at least the pitching direction; The radius of curvature of the convex surface in contact with the slider mounting portion is less than 0.10 mm and is 0.04 mm or more, and A suspension having a gain defined by the following formula of 0.9 or more. [Equation 1]

2. 2. The suspension of claim 1, A suspension in which the gain is 0.95 or more.

3. 2. The suspension of claim 1, A suspension in which the radius of curvature of the convex surface is less than 0.85 mm.

4. 2. The suspension of claim 1, The suspension has a flexure pitching resistance of 0.005 N or less acting on the contact portion with the convex surface when the slider mounting portion moves in the pitching direction.

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