Suspension for magnetic disk device, method for adjusting vibration characteristics thereof, and method for manufacturing the same

Abstract

A suspension for a magnetic disk device according to one embodiment includes a load beam having a recess and a flexure superimposed on the load beam. The load beam and the flexure are fixed to a first fixing portion and a second fixing portion located closer to the front end of the load beam than the first fixing portion. The flexure includes a tongue-shaped portion facing the recess and an outrigger connected to the tongue-shaped portion. The outrigger bends along the thickness of the load beam at a bend located between the recess and the first fixing portion in the longitudinal direction of the load beam.

Description

[0001] Cross-reference (reference to related applications)

[0002] This application is based on a prior application filed in Japan on October 20, 2021 (Japanese Patent Application No. 2021-171799), and enjoys priority from all matters disclosed in the prior application. Technical Field

[0003] The present invention relates to a suspension for a magnetic disk device used in a hard disk device or the like, a method for adjusting the vibration characteristics of the suspension, and a method for manufacturing the suspension for a magnetic disk device. Background Art

[0004] Hard disk devices (HDDs) are used in information processing devices such as personal computers. They consist of a magnetic disk that rotates around a spindle and a carriage that pivots around a pivot. The carriage has an actuator arm and is rotated about the pivot in the direction of the magnetic disk's track width by a positioning motor such as a voice coil motor.

[0005] The actuator arm is provided with a magnetic disk device suspension (hereinafter referred to as the suspension). The suspension includes a load beam and a flexure superimposed on the load beam. A slider constituting a magnetic head is provided on a universal joint formed near the front end of the flexure. The slider has an element (converter) for accessing, such as reading or writing data. These load beams, flexures, and sliders constitute a magnetic head universal joint assembly.

[0006] The universal joint assembly comprises a tongue-shaped member for mounting a slider and a pair of outriggers formed on either side of the tongue. These outriggers extend outwards of the flexure. Each outrigger is secured to the load beam at both ends, for example, by laser welding. Each outrigger is spring-like in its thickness, playing a crucial role in ensuring the universal joint motion of the tongue.

[0007] To increase disk recording density, the head gimbal assembly needs to be made more compact, and the slider needs to be positioned with greater precision on the disk's recording surface. Therefore, it is necessary to ensure the required gimbal motion of the head gimbal assembly while minimizing flexure vibration. As described in US Pat. No. 6,967,821 B2, JP2006-221726, and JP2010-866630A, it is known to locally dispose damping material on the gimbal to suppress flexure vibration.

[0008] Attaching damping material to the flexure can dampen its vibration, but this changes the flexure's rigidity. This change can adversely affect the movement of the universal joint. Furthermore, the essential step of attaching damping material increases the manufacturing cost of the suspension. Summary of the Invention

[0009] An object of the present invention is to provide a suspension for a magnetic disk device that can effectively suppress vibration of a flexure and has excellent performance.

[0010] A suspension for a magnetic disk device according to one embodiment includes a load beam having a recess and a flexure superimposed on the load beam. The load beam and the flexure are fixed to a first fixing portion and a second fixing portion located closer to the front end of the load beam than the first fixing portion. The flexure includes a tongue-shaped portion opposing the recess and an outrigger connected to the tongue-shaped portion. The outrigger has a curved portion located between the recess and the first fixing portion in the longitudinal direction of the load beam, and the outrigger bends along the thickness direction of the load beam at this curved portion.

[0011] For example, the bent portion is located between the tongue-shaped member and the first fixing portion in the longitudinal direction. The outrigger includes a first surface facing at least a portion of the load beam and a second surface opposite to the first surface in the thickness direction. The first surface may be convexly curved at the bent portion.

[0012] The outriggers may include a first outrigger and a second outrigger arranged side by side in the width direction of the load beam. In this case, the tongue-shaped member may be located between the first outrigger and the second outrigger in the width direction, and each of the first outrigger and the second outrigger may have a curved portion.

[0013] In a method for adjusting the vibration characteristics of a suspension for a magnetic disk device according to one embodiment, with respect to the specific vibration mode, the first gain of the flexure when the bent portion is not formed on the outrigger is measured, and with respect to the vibration mode, for each of a plurality of positions on the outrigger, the second gain of the flexure when the bent portion is formed at the position is measured, and the position at which the second gain obtained is less than the first gain among the plurality of positions is determined as the position at which the bent portion is formed when the suspension for the magnetic disk device is manufactured.

[0014] For example, the first gain and the second gain at the plurality of positions may be measured for each of the plurality of vibration modes. In this case, the position where the second gain is smaller than the first gain for at least one of the plurality of vibration modes at the plurality of positions is determined as the position where the bent portion is formed when the magnetic disk device suspension is manufactured.

[0015] In addition, in a method for adjusting the vibration characteristics of a suspension for a magnetic disk device according to one embodiment, with respect to the specific vibration characteristics, the first gain of the flexure is measured when the bending portion is not formed on the outrigger, and with respect to the vibration mode, the second gain of the flexure is measured for each of a plurality of bending angles of the outrigger at the bending portion, and the angle of the second gain obtained among the plurality of bending angles, which is smaller than the first gain, is determined as the bending angle of the bending portion when manufacturing the suspension for a magnetic disk device.

[0016] For example, the first gain and the second gain at the plurality of bending angles may be measured for each of a plurality of vibration modes. In this case, the bending angle at which the second gain obtained in at least one of the plurality of vibration modes at the plurality of bending angles is smaller than the first gain is determined as the bending angle of the bent portion when manufacturing the magnetic disk device suspension.

[0017] In the method of manufacturing a suspension for a magnetic disk device according to one embodiment, a suspension whose vibration characteristics are adjusted by the above-described adjustment method is manufactured.

[0018] According to the present invention, vibration of a flexure can be effectively suppressed, and a suspension for a magnetic disk device having excellent performance can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. 1 is a side view of an example of a magnetic disk device according to an embodiment.

[0020] Figure 2 yes Figure 1 A cross-sectional view of the magnetic disk device shown.

[0021] Figure 3 is a plan view of a suspension according to an embodiment.

[0022] Figure 4 is a plan view of a flexure according to an embodiment.

[0023] Figure 5 is a cross-sectional view of an outrigger and a load beam including a curved portion according to one embodiment.

[0024] Figure 6 1 and 2 are side views showing a flexure vibrating together with a load beam in (a) a first torsional mode, (b) a second torsional mode, and (c) a third torsional mode.

[0025] Figure 7 Side views of flexures vibrating in (a) the first torsional mode, (b) the second torsional mode, and (c) the third torsional mode.

[0026] Figure 8FIG. 1 is a diagram showing a specific example of the formation position of the bent portion of the suspension according to one embodiment.

[0027] Figure 9 This is a flowchart of an example of a method for adjusting vibration characteristics and a method for manufacturing a suspension according to an embodiment.

[0028] Figure 10 FIG. 1 is a diagram illustrating an example of measurement results of the first gain and the second gain of a suspension according to an embodiment. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0030] Figure 1 This is a perspective view showing an example of a hard disk drive (HDD) 1. This disk drive 1 includes a housing 2, multiple disks 4 that rotate around a spindle 3, a carriage 6 that can pivot around a pivot 5, and a positioning motor (voice coil motor) 7 for driving the carriage 6. The housing 2 is sealed by a cover (not shown).

[0031] Figure 2 1 is a cross-sectional view showing a portion of the magnetic disk device 1. Figure 1 and Figure 2 As shown, the carriage 6 includes a plurality of arms (carriage arms) 8. A suspension 10 is mounted on the front end of each arm 8. A slider 11 constituting a magnetic head is provided at the front end of each suspension 10. When the magnetic disk 4 rotates at high speed, air flows between the magnetic disk 4 and the slider 11, forming an air bearing.

[0032] exist Figure 2 In the example shown in FIG. 1 , the suspension 10 includes a base plate 12 . The base plate 12 is formed with a protrusion 12 a that is inserted into a hole 8 a formed in the arm 8 .

[0033] When the carriage 6 is rotated by the positioning motor 7 , the suspension 10 moves in the radial direction of the magnetic disk 4 , thereby moving the slider 11 to a desired track on the magnetic disk 4 .

[0034] Figure 3 This is a plan view of the suspension 10 according to this embodiment. The suspension 10 includes a load beam 20 and a flexure 30. In this embodiment, mutually orthogonal width directions X, Y, and Z are defined as shown in the figure. Furthermore, a sway direction S is defined as indicated by the arc-shaped arrow near the front end of the load beam 20. Each of the load beam 20, flexure 30, and suspension 10 has an elongated shape in the longitudinal direction Y.

[0035] The longitudinal direction Y is parallel to the central axis AX of the suspension 10. The load beam 20 and the flexure 30 have substantially symmetrical shapes with respect to the central axis AX.

[0036] The load beam 20 is made of a metal material and is formed into a flat plate shape. A tab 21 is provided at the front end of the load beam 20. The load beam 20 has a planar shape that gradually tapers toward the tab 21. Figure 2 The substrates 12 are shown connected.

[0037] The flexure 30 is superimposed on the load beam 20. The flexure 30 has a metal base 31, a wiring layer 32, and an insulating layer 33. The metal base 31 is made of a metal material such as stainless steel, and most of it faces the load beam 20.

[0038] The thickness of the metal base 31 is smaller than that of the load beam 20. The thickness of the metal base 31 is preferably 12-25 μm, and in one example is 20 μm. The thickness of the load beam 20 is in one example 30 μm.

[0039] The load beam 20 and the metal base 31 are secured by a pair of first securing portions 22L and 22R and a second securing portion 23. Laser spot welding, for example, can be used to secure these securing portions 22L, 22R, and 23. The first securing portions 22L and 22R are aligned along the width direction X. The distances from the first securing portions 22L and 22R to the central axis AX are the same. The second securing portion 23 is positioned closer to the tab 21 (the distal end of the load beam 20) than the first securing portions 22L and 22R. The second securing portion 23 is located on the central axis AX.

[0040] The wiring layer 32 is made of a highly conductive metal material such as copper and includes a plurality of wirings. The insulating layer 33 includes a plurality of layers including a base layer for each wiring and a layer covering each wiring. These layers can be made of, for example, polyimide.

[0041] Most of the wiring layer 32 and the insulating layer 33 are formed on the metal base 31. Figure 3 In the illustrated example, the wiring layer 32 and the insulating layer 33 include portions that are not supported by the metal base 31 , such as a pair of aerial wiring portions 34L, 34R.

[0042] Figure 4 3 is a plan view of the flexure 30 viewed from the metal base 31 side. Figure 3 and Figure 4 As shown, the metal base 31 has a front end portion 40 and a base end portion 41 spaced apart in the longitudinal direction Y. Figure 3 As shown, the front end portion 40 is located near the contact piece 21 and is fixed to the load beam 20 via the second fixing portion 23 .

[0043] The flexure 30 further includes a tongue 42, a first outrigger 50L, and a second outrigger 50R. In most of the tongue 42, an insulating layer 33 is laminated on the metal base 31. Figure 3 and Figure 4In the example of FIG, the outriggers 50L and 50R are formed of the metal base 31. That is, the outriggers 50L and 50R do not include the wiring layer 32 and the insulating layer 33.

[0044] The tongue 42 is located between the front end 40 and the base end 41 in the longitudinal direction Y. The outriggers 50L and 50R are respectively arranged on both sides of the tongue 42 in the width direction. In other words, the tongue 42 is located between the first outrigger 50L and the second outrigger 50R in the width direction X.

[0045] exist Figure 4 In the example shown, the tongue-shaped member 42 includes a first portion 42a, a second portion 42b, and a connecting portion 42c connecting the first portion 42a and the second portion 42b. The second portion 42b is located between the first portion 42a and the front end portion 40 in the longitudinal direction Y. The width of the connecting portion 42c is smaller than the widths of the first portion 42a and the second portion 42b.

[0046] like Figure 3 As shown, the slider 11 is mounted on the tongue 42. The tongue 42 has a plurality of terminals 42d for electrically connecting to the slider 11. These terminals 42d are provided on the second portion 42b.

[0047] The slider 11 has components such as MR elements that can convert magnetic signals and electrical signals. These components can be used to access the magnetic disk 4, such as writing or reading data. The slider 11, load beam 20, flexure 30, etc. constitute a head gimbal assembly.

[0048] like Figure 3 As shown, a recess 24 is formed near the front end of the load beam 20, protruding toward the tongue 42. The recess 24 is located on the central axis AX. The front end of the recess 24 contacts the tongue 42. The tongue 42 can swing about the front end of the recess 24 to perform the desired gimbal motion. The tongue 42, outriggers 50L and 50R, recess 24, and the like constitute the gimbal portion 43.

[0049] The first outrigger 50L includes a base end portion 51, a base end arm 52, a front end arm 53, and a connecting portion 54. The base end portion 51 is fixed to the load beam 20 via the first fixing portion 22L. The base end arm 52 extends from the base end portion 51 to the side of the tongue-shaped member 42. Figure 3 and Figure 4 In the example shown, the base arm 52 is inclined in the longitudinal direction Y so that it is farther away from the central axis AX as it approaches the tongue 42. One end of the front arm 53 is connected to the base arm 52, and the other end is connected to the front end portion 40. The connecting portion 54 is bent into a U shape and connects the front end of the base arm 52 to the first portion 42a of the tongue 42.

[0050] The second outrigger 50R has a shape that is line-symmetrical with the first outrigger 50L with respect to the central axis AX. That is, the second outrigger 51R has a base end 51, a base end arm 52, a front end arm 53, and a connecting portion 54. The base end 51 is fixed to the load beam 20 via the first fixing portion 22R. Figure 3 and Figure 4 As shown, the front end arms 53 of the outriggers 50L and 50R are integrally connected to the front end portion 40 on the central axis AX between the front end portion 40 and the tongue 42 .

[0051] The first outrigger 50L is bendable between the first fixing portion 22L and the second fixing portion 23 in the thickness direction Z. Similarly, the second outrigger 50R is bendable between the first fixing portion 22R and the second fixing portion 23 in the thickness direction Z. The tongue 42 is elastically supported by the outriggers 50L and 50R and is capable of swinging about the recess 24 as a fulcrum.

[0052] like Figure 3 and 4 As shown, the gimbal portion 43 is equipped with a pair of microactuator elements 44L and 44R. These microactuator elements 44L and 44R are both made of piezoelectric material and are arranged on both sides of the slider 11 in the width direction X. In the length direction Y, one end of the microactuator element 44L is connected to the first portion 42a of the tongue-shaped member 42, and the other end is connected to the second portion 42b of the tongue-shaped member 42. Similarly, one end of the microactuator element 44R in the length direction Y is connected to the first portion 42a, and the other end is connected to the second portion 42b.

[0053] The microactuator elements 44L and 44R have the function of causing the tongue 42 to swing in the swing direction S. Figure 3 and Figure 4 In the example shown, restricting members 45L and 45R are provided to suppress excessive swinging of the tongue 42. One end of the restricting member 45L is connected to the second portion 42b of the tongue 42, and the other end is connected to the front end arm 53 of the first outrigger 50L. One end of the restricting member 45R is connected to the second portion 42b of the tongue 42, and the other end is connected to the front end arm 53 of the second outrigger 50R. The restricting members 45L and 45R can be formed, for example, from the insulating layer 33.

[0054] The outriggers 50L and 50R are bent in the thickness direction Z at the bent portions 55, respectively. Figure 3 and 4 In the example of FIG. 5 , the bent portions 55 are respectively located on the base end arms 52 of the outriggers 50L and 50R.

[0055] Figure 5This is a cross-sectional view of the first outrigger 50L (base arm 52) and the load beam 20, including the curved portion 55. The base arm 52 has a first surface F1 facing the load beam 20 and a second surface F2 opposite the first surface F1. At the curved portion 55, the first surface F1 of the base arm 52 is convexly curved. In other words, the base arm 52 is curved so as to convexly face the load beam 20.

[0056] The bend angle θ of the base arm 52 at the bend 55 can have various values, for example, from 0.5° to 3°. For example, the bend angle θ corresponds to the angle at which the first surface F1 or the second surface F2 changes in the bend 55. The base arm 52 may have a curvature in the bend so as to bend smoothly.

[0057] The curved portion 55 is not necessarily Figure 5 As shown, it must be set at a position opposite to the load beam 20. Figure 3 The bent portion 55 may be provided at a portion of the base arm 52 that protrudes laterally from the load beam 20. Furthermore, the bent portion 55 may be provided at a position different from that of the base arm 52, as with the front arm 53.

[0058] The position and shape of the bent portion 55 in the second outrigger 50R are the same as those of the first outrigger 50L. That is, the bent portion 55 of the first outrigger 50L and the bent portion 55 of the second outrigger 50R are provided at the same position in the longitudinal direction Y.

[0059] The bent portions 55 of the outriggers 50L and 50R serve to suppress vibration (resonance) of the flexure 30. Various vibration modes may occur in the flexure 30. Representative examples of the vibration modes include a 1st torsional mode, a 2nd torsional mode, and a 3rd torsional mode.

[0060] Figure 6 and 7 1 and 2 are side views of the flexure 30 vibrating in (a) the first torsional mode, (b) the second torsional mode, and (c) the third torsional mode. Figure 6 The load beam 20 and the flexure 30 are shown. Figure 7 The load beam 20 is not shown.

[0061] exist Figure 6 In the first torsion mode shown in (a) and 7 (a), the outriggers 50L and 50R are deformed into a shape having a top (peak or valley). Figure 6 In (a), the first outrigger 50L is bent so that the center portion of the front arm 53 protrudes downward.

[0062] exist Figure 6In the secondary torsion mode shown in (b) and 7(b), the outriggers 50L and 50R are deformed into a shape having two tops (peaks or valleys). Figure 6 In (b), the first outrigger 50L is bent so that the center of the base arm 52 protrudes upward and the center of the front arm 53 protrudes downward.

[0063] exist Figure 6 In the third torsion mode shown in (c) and 7(c), the outriggers 50L and 50R are deformed into a shape having three tops (peaks or valleys). Figure 6 In (c), the first outrigger 50L is bent so that the center of the base arm 52 protrudes upward, the vicinity of the connecting portion 54 protrudes downward, and the center of the front arm 53 protrudes upward.

[0064] The specific positions at which the bent portions 55 are formed in the outriggers 50L and 50R can be determined by comprehensively considering various vibration modes including the first to third torsional modes.

[0065] Figure 8 1 is a schematic diagram showing a specific example of the formation position of the bent portion 55 of the suspension 10 according to this embodiment. Figure 1 Starting from, (a) is a graph showing the cross-sectional shape of the first outrigger 50L, (b) is a graph showing the displacement (amplitude) of the first outrigger 50L in the secondary torsion mode, and (c) is a graph showing the displacement (amplitude) of the first outrigger 50L in the tertiary torsion mode.

[0066] exist Figure 8 In the graph (a), the horizontal axis is the position in the length direction Y [mm] with the origin O as the reference (zero), and the vertical axis is the height from the slider 11 toward the recess 24 (from the tongue 42 to the recess 24). The origin O corresponds to the suspension 10 and Figure 1 The center of the connection between the arms 8 is shown. In one example, the origin O is the center of the raised portion 12a on the base plate 12 described above.

[0067] exist Figure 8 The graph (a) shows curves for the comparative example EX0 and the examples EX1, EX2, and EX3. These curves represent the shape of the first outrigger 50L along the line CL of the first outrigger 50L. Specifically, the comparative example EX0 corresponds to the shape of the first outrigger 50L without the bent portion 55, while the examples EX1, EX2, and EX3 correspond to the shape of the first outrigger 50L with the bent portions 55 provided at different positions.

[0068] exist Figure 8In the graph (a), the change (scale) on the vertical axis is greater than the change (scale) on the horizontal axis, allowing the cross-sectional shape of the first outrigger 50L to be more clearly understood. As can be seen from the graph of Comparative Example EX0, when the flexure 30 is attached to the load beam 20, even without the bent portion 55, the first outrigger 50L bends so that the area near the tongue 42 forms the top.

[0069] exist Figure 8 In the graphs (b) and (c), the horizontal axis is Figure 8 (a) The vertical axis represents the amplitude of the first outrigger 50L during vibration at the same position in the longitudinal direction Y. These graphs show the vibration profile in each mode.

[0070] Figure 8 The amplitude of the secondary torsional mode shown in (b) has a top P21 at the base arm 52 and a top P22 at the front arm 53 . Figure 8 The amplitude of the third torsional mode shown in (c) has a top P31 at the base arm 52 , a top P32 near the connection portion 54 , and a top P33 near the end of the front arm 53 .

[0071] like Figure 8 As shown by the multiple dotted lines in the figure, positions A, B, C, D, E, and F, arranged sequentially in the longitudinal direction Y, are defined. Position A passes through the center of the first fixing portions 22L and 22R. Position B corresponds to the position of the top P31 in the amplitude of the third-order torsional mode. Position C corresponds to the position of the top P21 in the amplitude of the second-order torsional mode. Position C also overlaps with the position where the aerial wiring portions 34L and 34R are bent in a protruding manner in the width direction X.

[0072] Position D corresponds to the top P32 of the third torsional mode. Position D also overlaps with the boundary between tongue 42 and connecting portion 54, and the boundary between base arm 52 and distal arm 53. Position E passes through recess 24. Position F passes through second fixing portion 23.

[0073] In the suspension 10 according to this embodiment, the inventors studied the formation positions of the bent portions 55, taking into account various vibration modes. As a result, they found that by providing the bent portions 55 of the outriggers 50L and 50R, respectively, between positions A and E, the vibration of the flexure 30 can be effectively suppressed. Furthermore, if the bent portions 55 are provided between positions B and D, the vibration suppression effect can be further enhanced.

[0074] exist Figure 8In Examples EX1, EX2, and EX3 shown in (a), the curved portion 55 is provided between position B and position D, more specifically, between position C and position D. The curved portion 55 in Example EX2 is closer to position D than the curved portion 55 in Example EX1. In addition, the curved portion 55 in Example EX3 is closer to position D than the curved portion 55 in Example EX2.

[0075] Next, a method of adjusting the vibration characteristics of the suspension 10 using the curved portion 55 and a method of manufacturing the suspension 10 will be described.

[0076] Figure 9 FIG2 is a flowchart showing an example of the adjustment method M1 and the manufacturing method M2. The adjustment method M1 determines the formation position and bending angle of the bent portion 55 and is executed before manufacturing the suspension 10. In the manufacturing method M2, the suspension 10 is manufactured by setting up a production line to achieve the formation position and bending angle of the bent portion 55 determined by the adjustment method M1.

[0077] In the adjustment method M1, first, the gains of the flexure 30 (outriggers 50L, 50R) in various vibration modes are measured for the suspension 10 without the bent portion 55 (step S11). The gain measured in step S11 is hereinafter referred to as the first gain.

[0078] Next, for the suspension 10 having the curved portion 55 , the gains of the curved portion 30 (outriggers 50L, 50R) in various vibration modes are measured (step S12 ). The gain measured in step S12 will be referred to as the second gain.

[0079] The measurements in steps S11 and S12 can be performed, for example, by simulation using a three-dimensional model of the suspension 10. These measurements can also be performed on a sample of an actually manufactured suspension 10. The vibration modes whose gains are measured in steps S11 and S12 are, for example, the aforementioned first-order torsional mode, second-order torsional mode, and third-order torsional mode.

[0080] In this embodiment, as an example, a plurality of three-dimensional models or samples in which the bent portion 55 is formed at different positions and bending angles are used to measure the second gain of each of the primary, secondary, and tertiary twist modes.

[0081] Figure 10 This figure is a diagram showing an example of the measurement results of the first gain and the second gain of the suspension 10 according to this embodiment. The figure shows the first and second gains measured in (a) the first torsional mode, (b) the second torsional mode, and (c) the third torsional mode, respectively.

[0082] exist Figure 10In (a), 10(b) and 10(c), the horizontal axis represents the formation position [mm] of the bent portion 55 in the longitudinal direction Y, and Figure 8 (a) The origin O is used as the reference (zero). The vertical axis is gain [dB]. Figure 10 The range of the formation position shown in (a), 10(b) and 10(c) is equivalent to Figure 8 The part between positions B and D.

[0083] exist Figure 10 In (a), 10(b) and 10(c), the squares superimposed on the vertical axis represent the first gain, the white circles represent the second gain when the bending angle θa is 1°, and the black circles represent the second gain when the bending angle θa is 2°.

[0084] The bending angle θa represents the angle of the bent portion 55 formed on the flexure 30 before being attached to the load beam 20. In the state where the flexure 30 is attached to the load beam 20, the outriggers 50L and 50R are as shown in FIG. Figure 8 (a) is bent. Therefore, the bending angle θa is Figure 5 The bending angles θ shown vary only slightly.

[0085] from Figure 10 (a) It can be seen that in the first torsion mode, even if the formation position and bending angle θa of the bent portion 55 are changed, the second gain hardly changes. The second gain is substantially the same as the first gain at any formation position.

[0086] like Figure 10 As shown in (b), in the secondary torsional mode, the second gain is generally smaller than the first gain at bending angles θa of 1° and 2°. The second gain is minimum at a bending angle θa of 1°, near 9.1 mm. The second gain is minimum at a bending angle θa of 2°, near 8.8 mm.

[0087] like Figure 10 As shown in (c), in the third-order torsional mode, when the bending angle θa is 1°, the second gain is generally smaller than the first gain. However, when the bending angle θa is 2°, the second gain partially exceeds the first gain. The second gain is minimized at around 9.0 mm when the bending angle θa is 1°, and at around 9.2 mm when the bending angle θa is 2°.

[0088] exist Figure 9After measuring the first and second gains in steps S11 and S12, the formation position and bending angle θa of the curved portion 55 in the actually manufactured suspension 10 are determined based on these gains (step S13). This determination can be made based on various conditions. In one example, the formation position and bending angle θa are selected so that the second gain is equal to or less than the first gain in at least one, and preferably most, of the vibration modes to be measured.

[0089] In obtaining Figure 10 In the cases of the first and second gains shown in (a), 10(b) and 10(c), since the fluctuation of the second gain is very small in the first torsion mode, the first torsion mode is not considered, and the formation position and bending angle θa are mainly determined based on the second gain in the second torsion mode and the third torsion mode.

[0090] For example, if it is necessary to specifically suppress vibration in the third-order torsional mode, the formation position can be determined at 9.0 mm, as indicated by the dashed box. Furthermore, at 9.0 mm, the second gain when the bending angle θa is 1° is smaller than the second gain when the bending angle θa is 2°, regardless of whether the flexure is in the second or third torsional mode. Therefore, the bending angle θa can be determined to be 1°. In this case, the second gain is smaller than the first gain even in the second-order torsional mode. Therefore, the bent portion 55 can reduce vibration of the flexure 30 in both the second and third torsional modes.

[0091] exist Figure 9 In the manufacturing method M2 of the suspension 10 shown, the components of the suspension 10, such as the load beam 20 and the flexure 30, are first manufactured (step S21). Subsequently, the bent portion 55 having the bending angle θa determined in step S13 is formed in the flexure 30 before being attached to the load beam 20 (step S22).

[0092] The bent portion 55 can be formed, for example, by press working using a mold or by irradiating the outriggers 50L and 50R with a laser. Figure 5 To form the curved portion 55 in the shape shown, a laser irradiation device irradiates the second surface F2 with a laser. The laser irradiation area heats up, and as the irradiated area cools, the outriggers 50L and 50R deform, causing the second surface F2 to become concave (and the first surface F1 to become convex). This results in a curved portion 55 in which the outriggers 50L and 50R are bent so that the first surface F1 becomes convex.

[0093] After the bent portion 55 is formed, elements such as the load beam 20 and the flexure 30 are assembled to complete the suspension 10 having good vibration characteristics (step S23 ).

[0094] although Figure 9 A case where elements such as the load beam 20 and the flexure 30 are assembled after forming a bent portion in the flexure is shown, but the bent portion may be formed after assembling elements such as the load beam 20 and the flexure 30 .

[0095] In addition, Figure 9 While the formation position and bending angle θa of the bend 55 are determined for the primary, secondary, and tertiary torsional modes, this is not limiting. When determining the formation position and bending angle θa of the bend 55, other vibration modes of the flexure 30 may be considered in addition to or in place of these vibration modes. Furthermore, not only the vibration modes of the flexure 30 but also coupled modes with the vibration of the load beam 20 may be considered. The bending angle θa is not limited to 1° or 2°. In one example, the bending angle θa may be set within a range of 0.5° to 3°.

[0096] According to the present embodiment described above, by providing the bent portions 55 in the outriggers 50L and 50R, it is possible to obtain the suspension 10 that effectively suppresses vibration around the gimbal portion 43 .

[0097] When the vibration characteristics are adjusted in this manner using the curved portions 55 of the outriggers 50L and 50R, the rigidity of the flexure 30 and the like is less likely to change compared to, for example, attaching a damping material to the flexure 30. This improves the vibration characteristics while minimizing the effects on the motion of the universal joint. Furthermore, since additional components such as damping material and the installation process are unnecessary, increases in the manufacturing costs of the suspension 10 can be minimized.

[0098] Furthermore, various advantageous effects can be obtained from this embodiment.

[0099] The above-described embodiment does not limit the scope of the present invention to the configuration disclosed in the embodiment. The present invention can be implemented by modifying the configuration disclosed in the embodiment into various forms.

[0100] For example, in the above embodiment, the outriggers 50L and 50R are as follows. Figure 5 The outriggers 50L and 50R are shown bent so that the first surface F1 is convex at the bent portion 55. However, if the vibration characteristics are satisfactorily improved, the outriggers 50L and 50R may be bent so that the second surface F2 is convex.

[0101] In addition, in the above embodiment, it is assumed that only one bent portion 55 is provided on the outriggers 50L and 50R. However, if vibration characteristics are well improved, the bent portions 55 may be provided at a plurality of locations on each of the outriggers 50L and 50R.

[0102] In addition, in the above embodiment, the Figure 9 The adjustment method M1 shown here determines the formation position and bending angle θa of the bent portion 55. As another example, the bending angle θa can be predetermined, and the formation position of the bent portion 55 having this bending angle θa can be determined using the adjustment method M1. In this case, in step S12, the second gain when the bent portion 55 is formed at each of multiple locations on the outriggers 50L and 50R under multiple vibration modes is measured. Furthermore, in step S13, the location where the second gain obtained in at least one of these multiple locations is smaller than the first gain in the vibration mode is determined as the formation position of the bent portion 55 in the actually manufactured suspension 10.

[0103] Alternatively, the location where the bent portion 55 is to be formed can be predetermined, and the bending angle θa can be determined by adjusting method M1, assuming that the bent portion 55 is formed at that location. In this case, in step S12, the second gain when the bent portion 55 is formed at that location is measured for each of a plurality of bending angles θa in a plurality of vibration modes. Furthermore, in step S13, the angle that exhibits a second gain smaller than the first gain in at least one vibration mode among the plurality of bending angles θa is determined as the bending angle θa of the bent portion 55 of the suspension 10 to be actually manufactured.

Claims

1. A suspension for a magnetic disk device, comprising: a load beam having a dimple, a flexure superimposed on the load beam, The load beam and the flexure are fixed to a first fixing portion and a second fixing portion that is closer to the front end of the load beam than the first fixing portion. The flexure has: a tongue-shaped member, said tongue-shaped member being opposite to said recess, an outrigger connected to the tongue, The outrigger is located at a bent portion between the recess and the first fixing portion in the longitudinal direction of the load beam and is bent in the thickness direction of the load beam, and The bent portion is provided at a portion of the outrigger that is opposite to the load beam, or the bent portion is provided at a portion of the outrigger that protrudes from the load beam. 2 . The magnetic disk device suspension according to claim 1 , wherein the bent portion is located between the tongue-shaped piece and the first fixing portion in the longitudinal direction.

3. The magnetic disk device suspension according to claim 1, wherein the outrigger has a first surface facing at least a portion of the load beam and a second surface opposite to the first surface in the thickness direction. The outrigger is bent at the bent portion so that the first surface is convex, and The bending angle of the outrigger at the bending portion is 0.5° to 3°.

4. The magnetic disk device suspension according to claim 1, wherein the outrigger includes a first outrigger and a second outrigger arranged in parallel in a width direction of the load beam. The tongue-shaped member is located between the first outrigger and the second outrigger in the width direction, and both the first outrigger and the second outrigger have a bent portion.

5. A method of adjusting the vibration characteristics of the suspension for a magnetic disk device according to claim 1, For a specific vibration mode, measuring a first gain of the flexure when the bending portion is not formed on the outrigger, For each of a plurality of positions on the outrigger, a second gain of the flexure when the bend is formed at the position is measured for the vibration mode. Among the plurality of positions, a position at which a second gain smaller than the first gain is obtained is determined as a position at which the bent portion is formed when manufacturing the magnetic disk device suspension.

6. The adjustment method according to claim 5, wherein the first gain and the second gain at the plurality of positions are measured for each of a plurality of vibration modes. A position where a second gain smaller than a first gain is obtained in at least one position in the plurality of vibration modes among the plurality of positions is determined as a position where the bent portion is formed when manufacturing the magnetic disk device suspension.

7. A method of adjusting vibration characteristics of the suspension for a magnetic disk device according to claim 1, For a specific vibration mode, measuring a first gain of the flexure when the bending portion is not formed on the outrigger, For the vibration mode, measuring a second gain of the flexure for each of a plurality of bending angles of the outrigger in the bending portion, Among the plurality of bending angles, an angle at which the second gain smaller than the first gain is obtained is determined as a bending angle of the bent portion when manufacturing the magnetic disk device suspension.

8. The adjustment method according to claim 7, wherein the first gain and the second gain at the plurality of bending angles are measured for each of a plurality of vibration modes. A bending angle at which the second gain smaller than the first gain is obtained in at least one of the plurality of vibration modes among the plurality of bending angles is determined as a bending angle of the bent portion when manufacturing the magnetic disk device suspension.

9. A method for manufacturing a suspension for a magnetic disk device, the vibration characteristics of the suspension being adjusted by the adjustment method according to any one of claims 5 to 8.

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