WO2003085669A1

WO2003085669A1 - Carriage sub assembly of disk device

Info

Publication number: WO2003085669A1
Application number: PCT/JP2003/004358
Authority: WO
Inventors: Satoru Suzuki; Ken Okura
Original assignee: Nhk Spring Co., Ltd.
Priority date: 2002-04-05
Filing date: 2003-04-04
Publication date: 2003-10-16
Also published as: JP2003303481A; AU2003236270A1

Abstract

A carriage sub assembly of a disk device for positioning a magnetic head slider at the tip of a drive arm relative to a magnetic disk medium capable of minimizing the deformation of the drive arm such as warpage caused by the press-fitting of the drive arm therein and formed so that the drive arm can be installed so as to hold a collar by press-fitting the press-fitted part of the collar into a press-fitted hole of the drive arm, characterized in that a press-fitted contact surface formed by the contact of the drive arm with the collar by the press-fitting is formed on either of the drive arm and the collar, and the lateral center of the press-fitted contact surface generally matches the center of the drive arm in plate thickness direction.

Description

Description Carriage subassembly for disk units Technical field

The present invention relates to a carriage subassembly for supporting a magnetic head slider of a magnetic or magneto-optical disk device built in a small information processing device such as a portable computer. Background art

FIG. 6 is a perspective view of a main part of a general magnetic disk drive, FIG. 7 is an exploded perspective view of a carriage subassembly of the disk drive, and FIG. 8 is a perspective view of a carriage subassembly of the disk drive. Is shown.

The magnetic disk device is an assembly carriage device for positioning one magnetic disk medium 110 rotating around the rotating shaft 111 and the magnetic head slider 3 on the track. 1 0 0. The assembly carriage device 100 is composed of a carriage 101 that can rotate around the rotation axis 4 and a voice coil motor (VCM) that drives the carriage 101 to rotate. Actuator 102 consisting of

The carriage 101 has a carriage sub-assembly 1 having a pair of drive arms 230, the base of which is attached to the rotating shaft 4, and the carriage subassembly 1 has a pair of drive arms 200, 30 at the distal ends of the drive arms 20, 30. The suspension device 2 is fixed. 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.

Carriage subassembly 1 includes a pair of drive arms 20 and 30 and a As shown in Fig. 7 and Fig. 8, the rotary shaft is provided with a cylindrical flange 12 at the middle part and press-fit parts 11 and 11 formed symmetrically at the upper and lower sides in a thin cylindrical shape with steps. It has a color 10 supported by 4. The pair of upper and lower drive arms 30 and 20 are press-fitted into the upper and lower press-fitting portions 11 and 11 respectively by pressing the press-fit holes 30a and 20a provided in the base into the same. Be integrated.

Since such a magnetic disk device is already known, further detailed description will be omitted.

Such conventional technologies have the following problems.

When the drive arms 30 and 20 are press-fitted into the press-fit portion 11 of the collar 10, the tips of the drive arms 30 and 20 move up and down, for example, as shown in FIG. The tip of the drive arm 20 is deformed so as to warp downward. The amount of reversal y is, for example, about 150〃 m for a drive arm having a length of 4 O mm from the axis center.

Therefore, a post-process (correction process) is required to correct the warpage of the drive arms 30 and 20 to within the standard 乂 ≤30〃, and the collar 10 and press-fit of the carriage subassembly 1 are required. It takes time and labor to assemble the unit and increases the cost.

The cause of such warpage associated with the press-fitting of the conventional drive arms 30 and 20 was pursued by measuring the shape (deformation) of the press-fitted portion after press-fitting, observing the cross section, and performing FEM analysis of the entire drive arm. It was found that this was caused by the shape of the press-fitting contact surface 11a on the outer peripheral surface of the press-fitted portion 11 of 10.

Looking at the detailed cross-section of the conventional press-fit part (D part in Fig. 9), as shown in Fig. 10, the press-fit part 11 1 The machining relief at the root of the outer peripheral surface 13 and the guide part 14 at the tip end The center of the press-fitting contact surface 1 1a in the rotation axis direction (width of the press-fitting contact surface) in the axial direction of B (the center point of the press-fitting contact surface) 1 1c is the press-fit hole of the drive arm 20 It is located axially inside (the upper side in Fig. 10) from the center line C of the wall thickness (plate thickness) of 20a. This As a result, the part where the press-fitting contact surface 11a inside the press-fitting hole 20a abuts receives a compressive force in the strange direction, that is, the drive arm is deflected by the compressive stress biased inside the drive arm 20. The bending moment acts downward with respect to the longitudinal direction of the drive arm 20, and as shown in Fig. 9, the inside of the drive arm extends relatively, and the free end is the outside (the ninth end). It is deformed (warped) in the direction shown below.

SUMMARY OF THE INVENTION In order to solve these problems, an object of the present invention is to provide a carriage subassembly of a disk device in which deformation such as warpage due to press-fit of a drive arm is minimized. Disclosure of the invention

In order to solve the above-mentioned problem, the present invention has a structure in which the drive arm is attached so as to sandwich the collar by press-fitting a press-fit portion of the collar into a press-fit hole of the drive arm. A carriage subassembly for positioning a magnetic head slider at the tip of the drive arm with respect to a magnetic disk medium, wherein a press-fitting contact surface where a drive arm and a collar come into contact by the press-fitting is a drive arm or 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.

The press-fitting contact surface is provided at the press-fitting portion of the collar, and a cut-out portion is provided on both sides of the press-fitting contact surface so that the center in the width direction of the press-fitting contact surface is aligned with the center of the plate thickness of the drive arm. Is formed.

Further, it is preferable that 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 one of a substantially circular shape, a trapezoidal shape, a triangular shape, and a polygonal shape. Brief description of the drawings.

1 (a) is a longitudinal sectional view of a collar of a carriage subassembly of a disk drive according to an embodiment of the present invention, (b) is a plan view thereof, and FIG. Fig. 1 is an enlarged view of part A of Fig. 1 (a), Fig. 3 is an enlarged view of part A of Fig. 1 (a) showing another cross-sectional shape of the press-fitting contact surface, and Fig. 4 is FIG. 1A is an enlarged view of a portion A of FIG. 1A showing another cross-sectional shape of the press-fitting contact surface, and FIG. 5 is an enlarged cross-sectional view of the press-fitting contact surface according to the embodiment of the present invention. FIG. 6 is a perspective view schematically showing a main part of an example of a general magnetic disk drive, and FIG. 6 is an exploded perspective view of a carriage subassembly of the general disk drive. FIG. 8 is a perspective view of a carriage subassembly of a general disk drive, and FIG. 9 is a carriage view of a conventional disk drive. It is an explanatory view showing a modification of the driving arm after the press-fitting process completes the sub-assembly, the first 0 Figure is a cross-sectional view of a D portion of FIG. 9. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1A is a longitudinal sectional view of a collar of a carriage subassembly of a disk drive according to an embodiment, and FIG. 1B is a plan view thereof. FIG. 2 is an enlarged detailed view of a portion A in FIG. 1 (a).

The carriage subassembly of the disk device according to this embodiment includes a pair of drive arms, for example, a lower drive arm, as shown in FIGS. 1 to 5 (the upper drive arm is omitted here). The press-fit portion 11 of the collar 10 is press-fitted into the press-fit hole 20 a of the drive arm 20, so that a pair of drive arms is attached so as to sandwich the collar 10. The carriage subassembly 1 uses a magnetic head slider (not shown) at the end of the drive arm to move the magnetic head slider to the magnetic disk medium. It is for positioning (see Fig. 6 and Fig. 8). The press fitting causes the collar 10 to be sandwiched between a pair of drive arms, and these are integrated.

In order to perform such press-fitting, a press-fitting contact surface 11a or 20b where the drive arm 20 and the collar 10 abut is formed on either the drive arm 20 or the collar 10. I have. The width of the press-fitting contact surface 11a or 2Ob (press-fitting contact surface width) The center 11c or 20c in the B direction should be substantially coincident with the center line C of the plate thickness of the drive arm 20. It is set.

The collar 10 is provided with a cylindrical flange 12 at an intermediate portion and a press-fit portion 11 formed in a symmetrically stepped thin cylindrical shape on both upper and lower sides, and is supported by a rotating shaft (not shown). 6 to 8).

-A pair of drive arms, for example, the lower drive arm 20 is integrated by press-fitting the press-fit hole 20a provided in the base into the lower press-fit portion 11 of the collar 10. The drive arm may be a single case instead of a pair.

In the collar 10 according to this embodiment, the press-fitting portion 11 is provided with a root cutout portion 11b and a tip guide portion (cutout portion) 11d on both sides of the outer peripheral surface. 1a is formed between these cutouts 11b and 11d. Further, the press-fitting contact surface 11a is formed by appropriately increasing the diameter of the press-fitting hole 20a, and is provided with a radial press-fit allowance due to a 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 excision portion 1 1b also serves as a relief for the corner portion where the flange portion 12 and the press-fitting portion 11 intersect. In addition, since the distal cutout 11 d also serves as a guide for press-fitting the press-fitting portion 11 into the press-fitting hole 20 a, the tip outer diameter of the distal cutout 11 d is equal to that of the press-fitting hole 20 a. It is set appropriately smaller than the inner diameter (for example, on the order of 1/10 mm or more).

As described above, the press-fitting contact surface 11a is aligned with the center line C of the thickness of the drive arm 20. The center of the press-fitting contact surface width B of the press-fitting contact surface 11a (the center of the press-fitting contact surface) 11c is formed to be vertically symmetrical so as to substantially coincide.

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 completely the same as the shape of the lower press-fitting contact surface 11a. .

The press-fitting contact surface 11a has a linear cylindrical shape in FIG. 2, but as shown in FIG. 3, the press-fitting contact surface 11a protrudes in the outer peripheral direction. It can also be formed in a trapezoidal cross section. The center of press-fitting contact surface width B at the top of page T of this trapezoid in the direction of B (center of press-fitting contact surface) 1 1c is set to approximately match the center line C of the thickness of the drive; Is done.

In addition, as shown in FIG. 4, the press-fitting contact surface 11a may be formed into a drum-shaped curved surface such as a substantially circular cross-sectional shape protruding in the outer peripheral direction. The center point (center of the press-fitting contact surface) 1 1c (apparently) in contact with the press-fitting hole 12a in the press-fitting contact surface 1 1a should substantially coincide with the center line C of the plate thickness of the drive arm 20. Is set to Further, although not shown, the press-fitting contact surface 11a may be formed in a triangular or polygonal cross-sectional shape in which the press-fitting contact surface 11a protrudes in the outer peripheral direction. In this case as well, the vertex (center of the press-fitting contact surface) of the triangular or polygonal cross-sectional shape (center of the press-fitting contact surface) that is (apparently) in contact with the press-fitting hole of the press-fitting contact surface is set to substantially match the center line C of the plate thickness of the drive arm. Is done. As described below, the reason why the above-described optimal configuration of the press-fitting contact surface 11a of the collar 1 10 is as described below is as follows. Based on the FEM analysis results of various cases regarding the amount of warp y at the tip of the drive arm due to the difference in the shape of a.

For example, a representative FEM analysis result for a drive arm with a thickness of 1.35 mm and a length of 4 O mm from the center of the rotation axis is shown below.

(Case 1) Conventional product: When the press-fitting contact surface width B is 0.65 mm from the upper end surface, the warpage amount y = 14.7 Um (Case 2): Press-fitting contact surface width B = Warp amount y when 1.15 mm from upper end surface

= 7.8 U m

(Case 3): When the press-fitting contact surface width B is "! .35 mm from the upper end surface (the same as the thickness of the driving arm), the amount of warping y = 0.74) L / m,

(Case 4): Press-fitting contact surface width B = When it is 0.65 mm symmetrically with respect to the center line of the thickness of the drive arm, the amount of warp y = 1.0 μm The closer the center 11 C of the press-fitting contact surface of the collar 10 to the center line C of the plate thickness of the driving arm, the closer the center 11 C of the press-fitting contact surface of the collar 10 approaches. It can be seen that the bending moment does not occur, and the value of the warpage amount y decreases sharply. In addition, as a result of studies such as FEM analysis, in order to satisfy the reference warpage amount y ≤ 30 jum, the position of the press-fitting contact surface center 11 c of the press-fitting contact surface width B of the collar must be It was found that the thickness of the drive arm should be within a range of 15 to 20% or less of the thickness C of the drive arm with respect to the center C of the thickness of the drive arm. Based on the above, the appropriate shape of δ for the press-fitting contact surface 11a is such that the center of the press-fitting contact surface 11c of the press-fitting contact surface width Β is always the center line of the drive arm thickness even after press-fitting. It is a curved surface such as a circular cross-sectional shape that tends to be aligned with C. According to this, in principle, the triangular or polygonal cross-sectional shape and then the trapezoidal cross-sectional shape are superior in order. it can.

The press-fit portion 11 of the collar 10 is slightly reduced in the radial direction when the drive arm is press-fitted, so that the inner diameter surface 11 e has a flange portion 1 2 as shown in FIG. As shown in FIG. 5, as an embodiment of the present invention, the upper and lower drive arms, for example, are slightly thicker (for example, about 0.1 mm) A press-fitting contact surface 20 b is formed on the inner surface of the press-fit hole 20 a of the lower drive arm 20 with a radial press-fit allowance appropriately smaller than the outer diameter 11 a of the press-fit portion of the collar 10. Have been. The protruding end 20 c of the press-fitting contact surface 20 b is It is formed vertically symmetrically so as to substantially coincide with the center of the plate thickness. In such a configuration, the position of the protruding end 20c of the protruding press-fitting contact surface 20b always coincides with the center line C of the plate thickness of the drive arm even after press-fitting, as in the above embodiment. It will be the arrangement to be. Therefore, the bending moment in the longitudinal direction of the drive arm does not occur, so that the value of the amount of warp y can be rapidly reduced. Then, in order to satisfy the reference warpage amount y ≤ 30 // m, similarly to the press-fitting contact surface center 11 c of the collar 10 in the above-described embodiment, a projecting press-fitting contact is required. Interfacing 2

The position of the protruding end 20c of 0b may be within a range of 15 to 20% or less of the thickness of the drive arm with respect to the center C of the thickness of the drive arm.

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

The carriage subassembly of the disk drive according to the present invention described in detail above is characterized in that, in the step of press-fitting the drive arm into the collar and assembling the same, the press-fitting of the drive arm with respect to the center line of the plate thickness of the drive arm is completed. The center of the press-fitting contact surface of the contact surface width is approximately the same, and no bending moment occurs in the longitudinal direction [S] of the drive arm, so the amount of warpage is greatly reduced. For this reason, the amount of warpage can be sufficiently suppressed within the standard of 30 im, so that the conventional repair process for correcting warpage can be omitted, and the conventional method contributes to a reduction in the manufacturing cost of the carriage subassembly. It has an excellent effect.

Claims

Scope of the claim 1. The drive arm is mounted so that the collar is sandwiched between the press-fitted part of the drive arm and the magnetic head at the tip of the drive arm. A carriage subassembly for positioning the slider with respect to the magnetic disk medium,

A press-fitting contact surface where the drive arm and the collar are in contact with each other by the press-fitting is formed in either the drive arm or the collar, and the center of the press-fitting contact surface in the width direction is the thickness of the drive arm. A carriage subassembly for a disk drive, which is substantially coincident with the center of the disc.

2. The press-fitting contact surface is provided on the press-fitting portion of the collar, and a cut-out portion is provided on both sides of the press-fitting contacting surface to align the center in the width direction of the press-fitting contact surface with the center of the plate thickness of the drive arm. 2. The carriage subassembly for a disk device according to claim 1, wherein the carrier subassembly is formed.

3. The carriage subassembly for a disk drive according to claim 1, wherein the press-fitting contact surface is formed in a sunk hole of a drive arm.

4. The disk according to any one of claims 1 to 3, wherein a cross section of the press-fitting contact surface is one of a substantially circular shape, a trapezoidal shape, a triangular shape, or a polygonal shape. Equipment carrier subassembly.