JP3492197B2 - How to make a head suspension assembly - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic storage device, and more particularly to a structure of a suspension that holds a magnetic transducer.

[0002]

2. Description of the Related Art As shown in FIG. 3, a magnetic disk device holds at least one magnetic disk 2 for recording and holding data on a plurality of concentric tracks, and when there are many magnetic disks 2, holds about 15 magnetic disks. A spindle 4 for rotating the magnetic disk, a slider 3 which floats or contacts in proximity to the magnetic disk, and a magnetic conversion for writing or reading data on the magnetic disk 2 attached to the slider 3. Device 1 and a positioning actuator 7 for moving the slider 3 in a direction traversing the track with respect to the magnetic disk 2 so that the magnetic converter 1 can access the track on the magnetic disk 2. And an arm attached to the actuator and coupled to the arm tip,
A suspension that holds the slider.

As shown in FIG. 4, the slider 3 having the magnetic transducer 1 mounted thereon has an air bearing surface 13 which is smooth and polished.
The magnetic disk 2 with a constant load W by the suspension 5
Being pressed against. In the magnetic disk device of the type called contact start stop, the air bearing surface 13 of the slider 3 is in close contact with the magnetic disk 2 when the device is stopped. When the magnetic disk 2 rotates,
A pressure is generated between the air bearing surface 13 and the magnetic disk 2, and the slider 3 flies over the magnetic disk 2 with a gap in which this pressure and the load W applied by the suspension 5 are balanced.

As shown in FIG. 5, a gimbal portion 8 having a structure for restraining the pitching and rolling movement of the slider 3 as much as possible is provided at the tip of the suspension 5, and the magnetic disk 2 is somewhat undulated. However, the slider 3 is not restricted by the surface of the suspension 5 and follows the magnetic disk 2 and maintains a substantially constant flying height. By keeping the flying height small, information is recorded on the surface of the magnetic disk 2 by the magnetic field generated from the magnetic converter 1, and the magnetic disk 2 is also recorded.
The magnetic field from the surface is sensed by the magnetic converter 1, and high density information recording / reproducing can be performed.

The suspension 5 has a mounting portion 10 to be attached to the arm 6, a load beam portion 11 having a structure that is hard to bend in the out-of-plane direction such as having flanges on both side edges, pitching of the slider 3 at the tip of the load beam portion 11, It has a gimbal portion 8 having a structure that does not restrain movement in the rolling direction as much as possible, and a bent portion 9 between the load beam portion 11 and the mounting portion 10. By having this bent portion 9, the slider 3 is a magnetic disk. Since the bending portion 9 bends in the direction in which the bending portion returns when it is placed on the slider 2, a load is generated on the slider 3.

Since the laminated magnetic disks 2 have variations in plate thickness and the arms 6 holding the suspension 5 also have variations in shape, the positional relationship between the magnetic disks 2 and the tips of the arms 6 varies. Occurs. The relative position of the magnetic disk 2 and the tip of the arm 6 in the direction perpendicular to the surface of the magnetic disk 2, that is, the variation of the set height 14 is
As shown in FIG. 1, the pitching direction angle θp of the load beam portion 11 of the suspension 5 with respect to the surface of the magnetic disk 2 varies.

The distance between the center of the mounting portion 10 of the most widely used conventional type suspension 5 and the center of the slider 3 is about 18 mm. If this length is long, the set height 14 as described above is set. The variation in the pitching direction angle θp due to the variation of 1 is small, and the flying of the slider 3 is hardly affected. Therefore, it is not necessary to consider the change in the pitching direction angle θp due to the variation in the set height 14 when designing the magnetic disk device and the suspension 5.

[0008]

In order to achieve a high recording density of the magnetic disk device, it is necessary to narrow the pitch of the concentric recording tracks, and the magnetic transducer 1 by the actuator 7 is applied to the magnetic disk 2. The positioning accuracy of must be highly accurate. Corresponding to this,
It is necessary to improve the vibration characteristics of the suspension (bring the resonance point of the suspension to a region beyond the normal control operation range). The most effective means for this is to reduce the length of the suspension 5.

However, as shown in FIG. 1, when the distance between the bending center 15 of the suspension 5 and the slider 3 is small, the amount of change in the angle of the load beam portion 11 with respect to the change in the set height 14 becomes large. . In a normal case, the slider 3 is in close contact with the magnetic disk 2 as shown in FIG. 2, but in an extreme case, if the pitching direction inclination θp becomes too large as shown in FIG. Of the slider 3, that is, the tip of the slider 3 in the direction opposite to the arm 6 contacts the magnetic disk 2.
There is a possibility that the end of the arm 6 on the side of the arm 6 is greatly separated from the magnetic disk 2.

This phenomenon is caused by the fact that the smaller the distance L (see FIG. 1) between the bending center 15 of the suspension 5 and the tip of the slider 3 in the direction opposite to the arm 6, the length L of the slider 3.
The smaller s (see FIG. 1), the smaller the load W on the slider 3, and the greater the rigidity Kp of the gimbal portion 8 around the slider center in the pitching direction, the more likely it is to occur.

The same thing can happen in the rolling direction of the slider 3. 6 and 7 are views seen from the tip end side of the slider 3. In a normal case, the slider 3 is in close contact with the magnetic disk 2 as shown in FIG. 6, but in an extreme case, As shown in FIG. 7, when the tip of the arm 6 has a large inclination or the suspension 5 has a large variation in the inclination in the rolling direction, as shown in FIG.
Although one side edge of the disk contacts the magnetic disk 2, a phenomenon may occur in which the opposite side edge of the disk greatly separates from the disk.

This phenomenon is more likely to occur as the width Bs of the slider 3 is smaller, the load W on the slider 3 is smaller, and the rigidity Kr of the gimbal portion around the slider center in the rolling direction is larger.

Such a large inclination of the slider 3 in the pitching direction or the rolling direction impedes the close contact of the slider 3 with the magnetic disk 2 and impairs the normal generation of pressure on the air bearing surface 13 when the magnetic disk 2 rotates. , Magnetic transducer 1
A normal gap between the magnetic disk 2 and the magnetic disk 2 is not formed, and normal recording / reproducing cannot be performed.

The distance L between the bending center 15 of the suspension 5 and the tip of the slider 3 in the opposite direction to the arm 6 is reduced in order to improve the vibration characteristics of the suspension 5 in response to the higher recording density of the magnetic disk device. In addition, the cost of the magnetic converter 1 and the slider 3 is reduced, and the flying followability to the magnetic disk 2 is improved.
In order to reduce the flying height and improve the recording density, it is essential to reduce the length Ls and the width Bs of the slider 3, and the contact force at the time of contact between the slider 3 and the magnetic disk 2 is required. In order to reduce the wear and damage on the surfaces of the slider 3 and the magnetic disk 2 and ensure the reliability of the magnetic disk device, it is essential to reduce the load applied to the slider 3.

In particular, for a suspension having a short length and a small slider, a problem associated with the shortening of the suspension (which is not a problem when the suspension is large) occurs. Specifically, the length Ls in the longitudinal direction of the slider 3, that is, the longitudinal direction of the suspension 5 is 1.4 mm or less, the length Bs in the lateral direction of the slider is 1.1 mm or less, and a load is generated. The distance L between the center of the bent portion 9 and the tip of the slider 3 on the side opposite to the arm 6 is 1
0 mm or less, the load W on the slider 3 is 9.8 mN
If it is less than (less than a small slider, including what is commonly called a pico slider), the risk of causing a large inclination in the pitching direction or the rolling direction of the slider 3 as described above increases.

[0016]

To solve the above problems, the present invention mainly adopts the following configurations.

A head suspension provided with a slider for holding the magnetic transducer, a bent portion for generating a load that presses the slider against the surface of the magnetic disk, and a gimbal portion for allowing pitching and rolling of the slider as much as possible. In the manufacturing method in the assembly, the length Ls (unit mm) in the longitudinal direction of the slider is 1.4 mm or less, the length Bs (unit mm) in the lateral direction of the slider is 1.1 mm or less, and the load is The distance L (unit: mm) between the center of the bent portion for generation and the tip of the slider opposite to the arm is 10 mm or less, and the load W on the slider is W.
Under the condition that (unit mmnewton) is less than 9.8 mN, the rigidity Kp (unit mmnewton mm / radian) in the pitching direction around the slider center of the gimbal portion is Kp <W / [{0.57 /(L×Ls)}+0.08], and the rigidity Kr (unit: millinewton millimeters / radian) in the rolling direction around the slider center of the gimbal portion satisfies the relationship of Kr <W / 0.11. How to make a head suspension assembly to meet.

Further, it is provided with a slider for holding the magnetic transducer, a bent portion for generating a load for pressing the slider against the surface of the magnetic disk, and a gimbal portion for enabling pitching and rolling of the slider as much as possible. In the manufacturing method of the head suspension assembly, the length Ls (unit: mm) in the longitudinal direction of the slider is 1.4 mm or less, and the length Bs (unit: mm) in the lateral direction of the slider is 1.1 m.
m or less, the distance L (unit: mm) between the center of the bent portion for generating a load and the tip of the slider opposite to the arm is 10 mm or less, and the load W (unit: newton) on the slider is Under the condition that it is less than 9.8 mN, the load W, the distance L, and the length Ls in the longitudinal direction of the slider satisfy the relationship of Ls <{W- (17 / L)} / 2.5. A method of producing a head suspension assembly so that the load W and the lateral length Bs of the slider satisfy the relationship of Bs <W / 5.2.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION First, an embodiment of the present invention,
The length Ls of the slider in the longitudinal direction is 1.4 mm or less, the length Bs of the slider lateral direction is 1.1 mm or less, and the center of the bent portion 9 for generating a load is opposite to the arm 6 of the slider 3. In the magnetic disk device using the slider and suspension in which the distance L from the tip of the slider is 10 mm or less, and the load W on the slider 3 is less than 9.8 mN, the slider 3 should hit the surface of the magnetic disk 3 on one side. Instead, the conditions for close contact should be sought.

Here, Ls is the length of the suspension 5 of the slider 3 in the longitudinal direction (unit: millimeter), W
Is the load on the slider 3 (unit: newton), L is the distance between the center of the bent portion 9 that generates the load and the tip of the slider 3 in the direction opposite to the arm 6 (unit: mm), K
p is the rigidity of the gimbal portion 8 around the center of the slider 3 in the pitching direction (unit: Newton millimeter / radian),
Respectively.

Bs is the length (unit: millimeter) in the direction perpendicular to the longitudinal direction of the suspension 5 of the slider 3,
Kr represents rigidity in the rolling direction around the center of the slider 3 of the gimbal portion 8 (unit: Newton millimeter / radian).

According to FIG. 1, the slider 3 is a magnetic disk 2.
The dynamics in the pitching direction for making close contact with the surface of will be described. When the pitching direction inclination θp of the gimbal mounting surface at the tip of the load beam shown in FIG. 1 occurs, one side of the slider 3 does not float up from the magnetic disk 2 as shown in FIG. 1 and closely contacts the magnetic disk 2 as shown in FIG. In order to do so, the rotational moment that the pitching direction inclination θp exerts on the slider 3 via the gimbal portion 8 is smaller than the rotational moment that the slider 3 is pressed by the load W.

A rotational moment that the inclination θp in the pitching direction exerts on the slider 3 via the gimbal portion 8, that is, θp
The moment required to bring the tilted slider into close contact with the disk is expressed by Kp × θp (1). The rotational moment at which the slider 3 is pressed by the load W is expressed by W × (Ls / 2) (2) because the operating position of the load W normally applied to the slider 3 is approximately the center of the slider 3. Therefore, the condition for the slider 3 to be in close contact with the magnetic disk 2 is expressed by W × (Ls / 2)> Kp × θp (3). When the acting position of the load W deviates from the center of the slider 3, (Ls / 2) in the above equation (3) may be replaced by the distance from the acting position of the load to the tip of the slider 3. If the gimbal portion 8 or the like has a structure in which a rotational moment in the pitching direction is applied to the slider 3 in advance, the rotational moment may be added to the right side Kp × θp of the above equation (3).

Since the load W varies, it is written as W → W-ΔW (4). It is necessary to consider the variation ΔW of the load W in addition to the variation of the suspension 5 alone, the variation due to the attachment of the suspension 5 to the arm 6 or the change of the set height 14. It is reasonable to set this amount to 30% of the target load W in consideration of some margin. That is, ΔW = 0.3 × W (5) Further, the pitching direction inclination θp includes the amount caused by the change amount Δhz of the set height 14 and the inclination error Δθp of the suspension 5 and the mounting surface of the arm 6, so that θp → (Δhz / L ) + Δθp …… (6) can be written. The amount of change Δhz of the set height 14 is the accumulation of the plate thickness error of the stacked magnetic disks 2 and the plate thickness error of the spacer 16 fitted between the stacked magnetic disks 2,
The accuracy of the formation of the arm 6 and the assembly error for setting the relative position between the spindle 4 supporting the magnetic disk 2 and the actuator 7 supporting the arm 6 are included. This error generally increases as the number of stacked magnetic disks 2 increases, but it is appropriate to set Δhz = 0.2 mm (7) at most. As for the pitching direction inclination error Δθp of the mounting surface of the suspension 5 and the arm 6, when the length Ls of the slider 3 is about 1.25 mm, Δθp = 0.035 [radian] ...... ( 8) needs to be considered. This inclination error Δθp is required to be reduced correspondingly when the slider 3 having a small size is used. Therefore, Δθp = 0.028 × Ls [radian] (9) be able to. Using the above conditions (4) to (9), (3) can be expressed as W> [{0.57 / (L × Ls)} + 0.08] × Kp [mN] (10) It The load W, the length L, and the gimbal portion pitching rigidity Kp of the suspension 5 are determined in accordance with these conditions, and the shape is designed to ensure the close contact between the slider 3 and the magnetic disk 2 in a normal magnetic disk device. You can

Kp is defined as the rigidity in the pitching direction around the center of the slider 3. This is experimentally measured by applying a couple to both ends in the longitudinal direction of the slider, and measuring the angle of the slider 3 in the pitching direction caused by the magnitude of the couple and the flexibility of the gimbal portion 8.

This value is obtained when the length Ls of the slider 3 is 1.2.
The value of 5 mm is about 38.2 mNmm / rad, which is reduced in proportion to the reduction of the slider 3. Therefore, if it is generalized, it can be expressed as Kp = 30.6 × Ls (11). Therefore, in the above equation (10), by rounding each coefficient to two significant figures, W> (17 / L) + (2.5 × Ls) [mN] ... (12) By adhering to these conditions and determining the load W and the length L of the suspension 5 and designing the shape, it is possible to secure the close contact between the slider 3 and the magnetic disk 2 in a normal magnetic disk device. The suspension 5 and the slider 3 may have any shape as long as the above relationship is maintained.

Regarding the rolling direction, according to FIG.
Requirements can be derived based on similar considerations. When the gimbal mounting surface at the tip of the load beam shown in FIG. 7 is tilted in the rolling direction θr, one side of the slider 3 moves to the position shown in FIG.
As shown in FIG. 6, in order to stick to the magnetic disk 2 as shown in FIG. 6, the rotation moment that the inclination θr in the rolling direction exerts on the slider 3 via the gimbal portion 8 causes the slider 3 to move due to the load W. It only needs to be smaller than the rotational moment that is pressed down.

The rotational moment that the rolling direction inclination θr exerts on the slider 3 via the gimbal portion 8 is expressed by Kr × θr (13). The rotational moment that the slider 3 is pressed by the load W is W × (Bs) because the operating position of the load W normally applied to the slider 3 is approximately the center of the slider 3.
/ 2) ……
It is represented by (14). Therefore, the condition for the slider 3 to be in close contact with the magnetic disk 2 is expressed by W × (Bs / 2)> Kr × θr (15). When the acting position of the load W deviates from the center of the slider 3, (Bs / 2) in the above equation (15) may be replaced with the distance from the acting position of the load to the end of the slider 3. When the gimbal portion 8 or the like has a structure in which a rotational moment in the rolling direction is applied to the slider 3 in advance, the rotational moment component may be added to the right side Kr × θr of the above equation (15). As in the case of the above pitching, ΔW = 0.3 × W (5). Further, the tilt θr in the rolling direction includes the tilt error of the suspension 5 and the mounting surface of the arm 6. In the slider having the magnetic transducer 1 at the center of the slider 3 in the width direction, a large allowable value is obtained from the viewpoint of the change in the flying height. When the width of the slider 3 is 1 mm, it is about θr = 0.0385 [radian] (16) (In the case of the suspension structure, a tilt error of this degree occurs due to an empirical rule based on experiments). . This tilt error θr is caused by the slider 3 having a small size.
When it is used, it is indispensable to reduce it correspondingly, so that θr = 0.0385 × Bs [radian] (17) can be set. Using the above conditions (5) and (17), (15) can be expressed as W> 0.11 × Kr [mN] (18). Observing these conditions, the load W of the suspension 5, the width Bs of the slider, the rolling rigidity K of the gimbal portion K
By determining r and designing the shape, it is possible to ensure the close contact between the slider 3 and the magnetic disk 2 in a normal magnetic disk device.

Kp is defined as the rigidity in the rolling direction around the center of the slider 3. This is experimentally measured by applying a couple force to both ends in the lateral direction of the slider, and the rolling direction angle of the slider 3 caused by the magnitude of the couple force and the flexibility of the gimbal portion 8. This value is
49m for slider 3 with width Bs of 1mm
It is about Nmm / rad, and is reduced in proportion to the slider 3 being made smaller. Therefore, if it is generalized, it can be expressed as Kr = 47 × Bs (19). Therefore, the above equation (18) is obtained by rounding each coefficient to two significant digits by rounding, and thus W> 5.2 × Bs. [MN] ... (20) By observing this condition and determining the load W of the suspension 5 and the width Bs of the slider 3 and designing the shape, the close contact between the slider 3 and the magnetic disk 2 in a normal magnetic disk device can be secured.

The above relationship (the relationship between (10) and (18) or the relationship between (12) and (20))
The shape of the suspension 5 and the shape of the slider 3 may be any shape as long as the above is satisfied.

[0031]

The length Ls in the longitudinal direction of the slider 3, that is, the longitudinal direction of the suspension 5 is 1.4 mm or less,
The lateral length Bs of the slider is 1.1 mm or less, and the distance L between the center of the bent portion 9 for generating a load and the tip of the slider 3 on the side opposite to the arm 6 is 10 m.
In a magnetic disk device using a slider and a suspension in which the load W on the slider 3 is less than 9.8 mN, the slider 3 adheres to the surface of the magnetic disk 3 without uneven contact, By rotating, the normal pressure can be generated on the air bearing surface of the slider 3, and the slider 3 can be stably levitated at the flying height as designed.

[Brief description of drawings]

FIG. 1 is a side view showing a positional relationship between a slider and a suspension in a pitching direction when a set height is largely changed.

FIG. 2 is a side view showing a positional relationship between normal sliders and suspensions in a pitching direction.

FIG. 3 is a side view showing a positional relationship between a slider, a suspension, and a magnetic disk in a magnetic disk device.

FIG. 4 is a side view of a slider.

FIG. 5 is a top view of the suspension.

FIG. 6 is a side view showing a positional relationship between normal sliders and suspensions in a rolling direction.

FIG. 7 is a side view showing the positional relationship in the rolling direction of the slider and the suspension when the inclination in the rolling direction changes significantly.

[Explanation of symbols]

1 Magnetic transducer 2 magnetic disk 3 slider 4 spindles 5 suspension 6 arms 7 Actuator 8 gimbal section 9 Bending section 10 Mounting part 11 Road beam section 12 base 13 Air bearing surface 14 set height 15 Center of bent part 16 spacers 17 cover

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Sugawara 2880, Kozu, Odawara-shi, Kanagawa Hitachi Storage Systems Division (72) Inventor Kosaku Wakatsuki 2880, Kozu, Odawara, Kanagawa Hitachi Storage Systems Co., Ltd. Within the business unit (72) Inventor Shinobu Hagiya 2880 Kokufu, Odawara-shi, Kanagawa Hitachi Storage Systems Division within (72) Inventor Eiichi Kodaira 2880 Kunifu, Odawara, Kanagawa Within Hitachi Storage System Division (56) Reference: JP-A-5-28682 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 21/16-21/26

Claims (2)

(57) [Claims] 1. A slider for holding a magnetic transducer, a bent portion for generating a load for pressing the slider against the surface of a magnetic disk, and a gimbal portion for allowing the pitching and rolling of the slider as much as possible. How to make the head suspension assembly
The length Ls (unit millimeter) of the slider in the longitudinal direction is 1.4 mm or less, and the length Bs (unit millimeter) of the slider in the lateral direction is 1.1 mm or less. Under the condition that the distance L (unit: millimeter) between the center of the bent portion and the tip of the slider opposite to the arm is 10 mm or less and the load W (unit: newton) on the slider is less than 9.8 mN. The rigidity Kp in the pitching direction around the slider center of the gimbal portion (unit: millinewton millimeter / radian) satisfies the relationship of Kp <W / [{0.57 / (L × Ls)} + 0.08] , and said rigid Kr rolling direction around the slider center of the gimbal portion (unit milli Newtons mm / radian) is, Kr <W / 0.11 So as to satisfy the relationship, the head suspension Assen
Head suspension characterized by creating yellowtail
How to make an assembly. 2. A slider for holding a magnetic transducer, a bent portion for generating a load for pressing the slider against a magnetic disk surface, and a gimbal portion for allowing pitching and rolling of the slider as much as possible. How to make the head suspension assembly
The length Ls (unit millimeter) of the slider in the longitudinal direction is 1.4 mm or less, and the length Bs (unit millimeter) of the slider in the lateral direction is 1.1 mm or less. Under the condition that the distance L (unit: millimeter) between the center of the bent portion and the tip of the slider opposite to the arm is 10 mm or less and the load W (unit: newton) on the slider is less than 9.8 mN. , The load W, the distance L, and the length Ls in the longitudinal direction of the slider satisfy the relationship of Ls <{W− (17 / L)} / 2.5 , and the load W and the lateral direction of the slider The head suspension assembly is designed so that the length Bs satisfies the relationship of Bs <W / 5.2.
Head suspension characterized by creating yellowtail
How to make an assembly.