JP2003303481A - Carriage sub assembly for disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carriage sub assembly for a disk device for which deformation such as a warp accompanying forcible fitting of a driving arm is reduced as much as possible. <P>SOLUTION: This carriage sub assembly for positioning a magnetic head slider at the tip of the driving arm to a magnetic disk medium is in the structure of attaching the driving arm so as to clamp a collar by forcibly fitting the forcible fitting part of the collar to the forcible fitting hole of the driving arm. A forcible fitting abutting surface where the driving arm and the collar are abutted by the forcible fitting is formed on either the driving arm or the collar and the center in a width direction of the forcible fitting abutting surface roughly matches with the center of the plate thickness of the driving arm. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carriage subassembly for supporting a magnetic head slider of a magnetic or magneto-optical disk device incorporated in a compact information processing device such as a portable computer.

[0002]

2. Description of the Related Art FIG. 6 is a perspective view of a main part of a general magnetic disk apparatus, FIG. 7 is an exploded perspective view of a carriage subassembly of the disk apparatus, and FIG. 8 is a perspective view of a carriage subassembly of the disk apparatus.

The magnetic disk device comprises one magnetic disk medium 110 which rotates around a rotary shaft 111, and an assembly carriage device 100 for positioning the magnetic head slider 3 on a track. The assembly carriage device 100 is composed of a carriage 101 rotatable about the rotation shaft 4, and an actuator 102 configured to rotate the carriage 101, for example, a voice coil motor (VCM).

The carriage 101 comprises a carriage subassembly 1 having a pair of drive arms 20, 30 whose base is attached to the rotary shaft 4, and the drive arms 20, 3 are provided.
The suspension device 2 is fixed to the front end portion of 0. A magnetic head slider 3 is fixed to the tip of the suspension device 2. Reference numeral 103 in FIG. 6 denotes a flexible printed circuit board connected to the suspension device 2.

In addition to the pair of drive arms 20 and 30, the carriage subassembly 1 has a cylindrical flange portion 12 in the middle and a stepped thin-walled cylindrical shape symmetrically on both upper and lower sides, as shown in FIGS. 7 and 8. The collar 10 is provided with the press-fitting portions 11 and 11 formed on the rotary shaft 4. The pair of upper and lower drive arms 30, 20 are integrated with the collar 10 by press-fitting the press-fitting holes 30a, 20a provided in the base into the upper and lower press-fitting portions 11, 11, respectively. Since such a magnetic disk device is already known, a detailed description thereof will be omitted.

[0006]

However, such a conventional technique has the following problems. When the drive arms 30 and 20 are press-fitted into the press-fitting portion 11 of the collar 10, the tip ends of the drive arms 30 and 20 are vertically moved, for example, as shown in FIG.
As shown in, the distal end of the lower drive arm 20 is deformed so as to warp downward. The warp amount y is, for example,
150 μm for a drive arm 40 mm in length from the axis center
Before and after. Therefore, a post-process (correction process) for correcting the warp of the drive arms 30 and 20 to be within the standard y ≦ 30 μm is necessary, and it takes time and effort to integrally assemble the carriage subassembly 1 with the collar 10. It was a cost increase.

The cause of the warp associated with the press-fitting of the conventional drive arms 30 and 20 is the shape (deformation) of the press-fitting part after the press-fitting.
As a result of measurement, cross-section observation, FEM analysis of the entire drive arm, and the like, it was found that it was due to the shape of the press-fitting contact surface 11a on the outer peripheral surface of the press-fitting portion 11 of the collar 10. A detailed cross section of the conventional press-fitting portion (D portion in FIG. 9) is shown in FIG.
As shown in FIG.
Also, the axial center point (press-fit contact surface center point) 11c of the axial length (press-fit contact surface width) B of the press-fit contact surface 11a excluding the guide portion 14 at the tip end is press-fitted into the drive arm 20. Hole 2
Axial inner side of the center line C of the wall thickness (plate thickness) of 0a (see FIG. 1).
At 0, it is located on the upper side). Therefore, the press-fitting hole 20a
A compressive stress in the radial direction is applied to a portion where the press-fitting contact surface 11a on the inner side of the drive arm abuts, that is, due to a compressive stress biased toward the inner side of the drive arm 20, a bending moment is generated downward in the longitudinal direction of the drive arm 20. As shown in FIG. 9, the inner side of the drive arm relatively extends, and the free end of the drive arm deforms (warps) outward (downward in FIG. 9).

In order to solve these problems, it is an object of the present invention to provide a carriage subassembly for a disk device in which deformation such as warpage due to press fitting of a drive arm is minimized.

[0009]

In order to solve the above-mentioned problems, the present invention provides a structure in which a drive arm is attached so as to sandwich the collar by press-fitting a press-fitting portion of the collar into a press-fitting hole of the drive arm. A carriage subassembly for positioning the magnetic head slider at the tip of the drive arm with respect to the magnetic disk medium, wherein the press-fitting contact surface where the drive arm and the collar contact by the press-fitting is the drive arm or the collar. The center of the press-fitting contact surface in the width direction substantially coincides with the center of the plate thickness of the drive arm.

Further, the press-fitting contact surface is provided in the press-fitting portion of the collar, and the widthwise center of the press-fitting contact surface is aligned with the center of the plate thickness of the drive arm on both sides of the press-fitting contact surface. It is characterized in that a cut portion is formed.

Further, the press-fitting contact surface is formed in a press-fitting hole of the drive arm.

The cross section of the press-fitting contact surface is substantially circular,
It is characterized by being one of a trapezoid, a triangle or a polygon.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Figure 1 (a)
FIG. 3A is a vertical cross-sectional view of a collar of a carriage subassembly of a disk device according to an embodiment, and FIG. FIG. 2 is an enlarged detailed view of a portion A of FIG.

As shown in FIGS. 1 to 5 (the upper drive arm is omitted here), the carriage subassembly of the disk drive according to this embodiment has a pair of drive arms, for example, the lower drive arm 20. Press-fit hole 20a
When the press-fitting portion 11 of the collar 10 is press-fitted into the, the pair of drive arms is attached so as to sandwich the collar 10. The carriage subassembly 1 is for positioning a magnetic head slider (not shown) at the tip of the drive arm with respect to the magnetic disk medium (see FIGS. 6 and 8). Then, by press fitting the collar 1
0 becomes a state in which a pair of drive arms are sandwiched, and these are integrated.

In order to perform such press-fitting, a press-fitting contact surface 11a or 20b on which the drive arm 20 and the collar 10 abut is formed on either the drive arm 20 or the collar 10. The width (press-fit contact surface width) B center 11c or 20c of the press-fit contact surface 11a or 20b is the drive arm 20.
It is set so as to substantially coincide with the center line C of the plate thickness.

The collar 10 has a cylindrical flange 12 in the middle.
Also, the press-fitting portions 11 formed symmetrically in a stepped thin-walled cylindrical shape are provided on both the upper and lower sides, and are supported by a rotation shaft (not shown).
Through FIG. 8). The pair of drive arms, for example, the lower drive arm 20 is integrated by press-fitting the press-fitting hole 20a provided in the base portion into the press-fitting portion 11 on the lower side of the collar 10. The drive arms may be a single case instead of a pair.

In the collar 10 according to this embodiment, a root cutout portion 11b and a tip guide portion (cutout portion) 11d are formed on both sides of the outer peripheral surface of the press-fitting portion 11, and the press-fitting contact surface 11 is formed.
The a is formed between the cutouts 11b and 11d. Further, the press-fitting contact surface 11a is appropriately larger than the diameter of the press-fitting hole 20a, and is provided with a radial press-fitting margin due to the difference in diameter between the two. The cutouts 11b and 11d are for aligning the center 11c of the press-fitting contact surface width B with the center line C of the plate thickness of the drive arm 20. At the same time, the root cutting portion 11b also serves as a relief for processing the corner portion where the collar portion 12 and the outer peripheral surface of the press-fitting portion 11 intersect. In addition, the tip cutting portion 11
Since d also serves as a guide when the press-fitting portion 11 is press-fitted into the press-fitting hole 20a, the tip outer diameter of the tip cutting portion 11d is appropriately set (for example, on the order of 1/10 mm or more) smaller than the inner diameter of the press-fitting hole 20a. . In this way, the press-fitting contact surface 1
1a is vertically symmetrical so that the center (press-fitting contact surface center) 11c of the press-fitting contact surface width B of the press-fitting contact surface 11a substantially coincides with the center line C of the plate thickness of the drive arm 20. ing. It goes without saying that the shape of the press-fitting contact surface 11a of the press-fitting portion 11 into which the upper drive arm (not shown) is press-fitted is exactly the same as the shape of the lower press-fitting contact surface 11a.

The press-fitting contact surface 11a has a linear cylindrical surface shape in FIG. 2, but as shown in FIG.
It is also possible to form the press-fitting contact surface 11a in a trapezoidal cross-sectional shape that is provided so as to project in the outer peripheral direction. The center (press-fitting contact surface center) 11c in the width B direction of the press-fitting contact surface, which is the top of the trapezoid, is set so as to substantially coincide with the center line C of the plate thickness of the drive arm 20.

Further, as shown in FIG. 4, the press-fitting contact surface 11
It is also possible to form a into a drum-shaped curved surface having a substantially circular cross-sectional shape such that a is projected in the outer peripheral direction. The center point (center of the press-fitting contact surface) 11c (apparently) contacting the press-fitting hole 12a in the press-fitting contact surface 11a is the center line C of the plate thickness of the drive arm 20.
Is set to substantially match with.

Further, although not shown, the press-fitting contact surface 11a
Can also be formed in a triangular or polygonal cross-sectional shape protruding in the outer peripheral direction. Also in this case, the apex (center of the press-fitting contact surface) of the triangular or polygonal cross-sectional shape (apparently) contacting the press-fitting hole of the press-fitting contact surface (center of the press-fitting contact surface) is set to substantially coincide with the center line C of the plate thickness of the drive arm. To be done.

The press-fitting contact surface 11a of the collar 10 described above
The reason why the optimum shape and structure of the collar 10 has been achieved is, as will be described below, the press-fitting contact surface 1 of the collar 10 in the plate thickness direction of the drive arm.
According to the FEM analysis results in various cases regarding the warp amount y of the tip of the drive arm due to the difference in the shape of 1a.

For example, a typical FEM for a drive arm having a plate thickness of 1.35 mm and a length of 40 mm from the center of the rotation axis.
The analysis results are shown below. (Case 1) Conventional product: Press fit contact surface width B = 0 from the upper end surface.
In case of 65 mm, warp amount y = 174.7 μm (case 2): press-fitting contact surface width B = 1.15 m from the upper end surface
In case of m, warp amount y = 7.8 μm (case 3): press-fitting contact surface width B = 1.35 m from the upper end surface
In the case of m (same as the plate thickness of the drive arm), the warp amount y = 0.
74 μm, (Case 4): press-fit contact surface width B = warp amount y in the case of 0.65 mm symmetrical to the center line of the plate thickness of the drive arm
= 1.0 μm

As is clear from this, the closer to the position where the press-fitting contact surface center 11c of the press-fitting contact surface width B of the collar 10 is aligned with the center line C of the plate thickness of the drive arm, the longer the longitudinal direction of the drive arm. It can be seen that the value of the warp amount y rapidly decreases because the bending moment with respect to is not generated. Furthermore, as a result of examination such as FEM analysis, the standard warp amount y
In order to satisfy ≦ 30 μm, the position of the press-fitting contact surface center 11c of the press-fitting contact surface width B of the collar is 15 to 20% or less of the plate thickness of the drive arm with respect to the center C of the plate thickness of the drive arm. It turned out that it should be within the range of.

From the above, the optimum shape of the press-fitting contact surface 11a is that the position of the press-fitting contact surface center 11c of the press-fitting contact surface width B is always relative to the center line C of the plate thickness of the drive arm even after press-fitting. It is a curved surface having a circular cross-sectional shape or the like that is likely to be aligned with each other, and accordingly, in principle, it can be said that a triangular or polygonal cross-sectional shape and a trapezoidal cross-sectional shape are excellent in this order.

The press-fitting portion 11 of the collar 10 is slightly reduced in diameter in the radial direction when the drive arm is press-fitted.
As shown in FIG. 1A, 1e is formed slightly thicker (for example, about 0.1 mm) than the inner diameter surface 12a of the collar portion 12.

As an embodiment of the present invention, as shown in FIG. 5, upper and lower drive arms, for example, lower drive arm 2
0 press-fit hole 20a inner diameter surface of collar 10 press-fit portion outer diameter 11
A protruding press-fitting contact surface 20b having a radial press-fitting margin that is appropriately smaller than a is formed. This press-fitting contact surface 20b
The protruding end 20c is formed in a vertically symmetrical shape so as to substantially coincide with the center of the plate thickness of the drive arm 20.

With such a configuration, as in the above-described embodiment, the position of the protruding end 20c of the protruding press-fitting contact surface 20b is always aligned with the center line C of the plate thickness of the drive arm even after press-fitting. Become. Therefore, no bending moment is generated in the longitudinal direction of the drive arm, so that the warp amount y can be rapidly reduced. In order to satisfy the standard warp amount y ≦ 30 μm, the position of the projecting end 20c of the projecting press-fitting contact surface 20b is the same as the press-fitting contact surface center 11c of the collar 10 in the above-described embodiment. 15 to 2 of the thickness of the drive arm with respect to the center C of the thickness of
It may be in the range of 0% or less.

The cross-sectional shape of the projection-shaped press-fitting contact surface 20b of this embodiment may be substantially circular, trapezoidal, triangular or polygonal.

[0029]

The carriage subassembly of the disk device according to the present invention, which has been described in detail above, has a structure in which the drive arm is press-fitted into the collar to integrally assemble the collar with respect to the center line of the plate thickness of the drive arm. Since the center of the press-fitting contact surface of the press-fitting contact surface width is substantially coincident with each other and a bending moment in the longitudinal direction of the drive arm is not generated, the warp amount is significantly reduced. Therefore, the amount of warpage is 30μ
Since it can be sufficiently suppressed within m, the conventional correction process for correcting the warp can be omitted, and an unprecedented excellent effect such as a reduction in the manufacturing cost of the carriage subassembly can be obtained.

[Brief description of drawings]

1A is a vertical cross-sectional view of a collar of a carriage subassembly of a disk device according to an embodiment of the present invention, and FIG. 1B is a plan view thereof.

FIG. 2 is an enlarged view of a portion A of FIG.

FIG. 3 is an enlarged view of part A of FIG. 1A showing another cross-sectional shape of the press-fitting contact surface.

FIG. 4 is a view showing still another cross-sectional shape of the press-fitting contact surface.
It is an enlarged view of the A section of (a).

FIG. 5 is an enlarged sectional view of a press-fitting contact surface according to the embodiment of the present invention.

FIG. 6 is a perspective view schematically showing a main part configuration of an example of a general magnetic disk device.

FIG. 7 is an exploded perspective view of a carriage subassembly of a general disc device.

FIG. 8 is a perspective view of a carriage subassembly of a general disk device.

FIG. 9 is an explanatory diagram showing deformation of the drive arm after the press-fitting process of the carriage subassembly of the conventional disk device is completed.

10 is a cross-sectional view of a D part of FIG.

[Explanation of symbols]

1 Carriage subassembly 2 Suspension device 3 Magnetic head slider 4,111 rotation axis 10 colors 11 Press-fitting section 11a Press-fitting contact surface or press-fitting part outer diameter 11b Root excision part 11c Center of press-fitting contact surface 11d, 14 Tip guide (cutting) part 11e Press-fitting part inner diameter surface 12 collar part 12a mounting hole 13 Processing escape 20 Lower drive arm 20a, 30a Press fit hole 20b Protrusion-shaped press-fitting contact surface 30 Upper drive arm 100 assembly carriage device 101 carriage 102 actuator 103 Flexible printed circuit board 110 magnetic disk media B Press-fitting contact surface width y Warpage amount

Claims (4)

[Claims] 1. A structure in which a drive arm is attached so as to sandwich the collar by press-fitting a press-fitting portion of the collar into a press-fitting hole of the drive arm, and the magnetic head slider at the tip of the drive arm is attached to a magnetic disk medium. A carriage subassembly for positioning relative to the drive arm, the press-fit contact surface on which the drive arm and the collar contact by press-fitting is formed on either the drive arm or the collar, and the width of the press-fit contact surface. A carriage subassembly for a disk drive, wherein the center of the direction substantially coincides with the center of the plate thickness of the drive arm. 2. The press-fitting contact surface is provided in the press-fitting portion of the collar, and is cut on both sides of the press-fitting contact surface to align the widthwise center of the press-fitting contact surface with the center of the plate thickness of the drive arm. 2. The carriage subassembly for a disk drive according to claim 1, wherein a portion is formed. 3. The carriage subassembly of the disk device according to claim 1, wherein the press-fitting contact surface is formed in a press-fitting hole of the drive arm. 4. The carriage of the disk device according to claim 1, wherein the cross section of the press-fitting contact surface is one of a substantially circular shape, a trapezoidal shape, a triangular shape, and a polygonal shape. Subassembly.