JPH0594668A - Magnetic disk driving device - Google Patents

Abstract

PURPOSE:To enable to easily assemble a spindle motor in a state that uniform pressure is applied, by having a structure that a centroid of a base plate and a shaft center of a shaft member of the spindle motor nearly coincides. CONSTITUTION:An adjusting member for centroid 78 and an upper adjusting member for centroid 79 are provided by centering them at one edge surface side with respect to the shaft center of the shaft member 26 of the spindle motor A and the base area is relatively well-balanced the moment to a broad other edge part side, and the centroid of the base plate 10 nearly coincides with the shaft center of the shaft member 26 of the spindle motor. In this case, when the base plate is fixed and an annular member provided on the base plate, the shaft member of the spindle motor and bearings or a bearing fixing member are assembled by applying pressure, application of uniform pressure becomes practicable and the magnetic disk driving device mounted with the spindle motor without eccentricity of the shaft member is easily obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive device.

[0002]

2. Description of the Related Art A magnetic disk drive device includes a spindle motor for driving the magnetic disk in the device, a magnetic disk mounted on a hub of the spindle motor, and writing and reading information to and from the magnetic disk in the vicinity of the magnetic disk. It has a head for performing, an arm portion for holding the head, a pivot for rotatably supporting the arm portion, and a voice coil motor for rotating the arm portion.

In order to arrange these parts efficiently in the magnetic disk drive, the base of the magnetic disk drive is generally rectangular or elliptical, and the spindle motor for driving the magnetic disk is the base. Many products are placed at a position deviated to one side from the center of, and a voice coil motor is placed on the other side.

In many magnetic disk drive devices, a base defining the disk chamber and an annular wall portion for fixing a bearing or a bearing fixing member of a spindle motor for driving the magnetic disk are integrally formed.

By the way, in a magnetic disk drive apparatus in which a base for defining such a disk chamber and an annular wall portion for fixing a bearing or a bearing fixing member of a spindle motor for driving a magnetic disk are integrally formed, With the annular wall as a reference, a bearing or a bearing fixing member is mounted parallel to the axial direction of the annular wall, and the shaft member is press-fitted while applying pressure evenly in the same direction as the axial direction of the annular wall. Is being assembled.

[0006]

However, in this type of magnetic disk drive, the center of gravity of the base and the spindle for driving the magnetic disk are fixed because the annular wall of the base is fixed and pressure is applied. There is a phenomenon in which the shaft center of the shaft member of the motor does not substantially coincide with each other and uniform pressure is hardly applied to the bearing or the bearing fixing member.

Therefore, the shaft member is eccentrically fixed,
There was a high possibility that the bearing or the bearing fixing member would be fixed due to uneven pressure.

The present invention has been made in view of the above facts, and an object thereof is to have a structure in which the center of gravity of a base in a magnetic disk drive and the axis of a shaft member in a spindle motor are substantially aligned. Thus, even if the base is fixed during the assembly of the spindle motor and the shaft member is press-fitted, eccentricity of the shaft member does not easily occur, and it is possible to mount the bearing or the bearing fixing member and the shaft member in a state where pressure is applied evenly. It is to provide a magnetic disk drive device.

[0009]

To achieve the above object, in the magnetic disk drive of the present invention, the axis of the shaft member of the spindle motor and the center of gravity of the base of the magnetic disk drive are substantially aligned. What I did,
A center of gravity adjusting member is attached to one end of the base, or one end of the base is extended outward.

[0010]

Since the center of gravity of the base in the magnetic disk drive and the shaft center of the shaft member in the spindle motor substantially coincide with each other, the shaft of the annular wall portion of the bearing or the bearing fixing member base is referred to the base when the spindle motor is assembled. It becomes possible to wear while applying uniform pressure in the same direction as the direction of the heart. Further, since the press-fitting of the shaft member is the same as the axial direction of the annular wall portion, it is possible to easily assemble the spindle motor in a state where the shaft member is not eccentric and the bearing or the bearing fixing member is evenly pressed. You can

[0011]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of a magnetic disk drive apparatus according to a first embodiment of the present invention, and FIG.
It is a I-0-II sectional view taken on the line. However, FIG. 1 is shown with the lid of the disc chamber removed.

Reference numeral 10 denotes a base of the disk chamber 11, which is made of aluminum. An annular recess 12 is provided on the right side of the center of the base 10 in FIG. 1, and an annular wall 14 is erected from the inner peripheral portion of the bottom of the annular recess 12 toward the inside of the disk chamber 11. The inner peripheral portion of the annular wall portion 14 is a through portion. Also, the annular recess 12
The outer diameter of the outer peripheral portion of the opening is slightly enlarged to form the enlarged diameter portion 16.

Reference numeral 18 is a first bearing, and 20 is a second bearing. The outer races of the first bearing 18 and the second bearing 20 are fixed to the inner peripheral wall 14a of the annular wall portion 14 with an adhesive. 22 is a cylindrical spacer interposed between the first bearing 18 and the second bearing 20.

Reference numeral 24 is a cup-shaped rotor hub. A hollow shaft member 26 is provided so as to project inside the central portion of the rotor hub 24, and the outer peripheral surface of the shaft member 26 has the first bearing 1
The inner rings of the second bearing 8 and the second bearing 20 are fixed by an adhesive.

Reference numeral 28 denotes a stator core fixed to the outer peripheral wall 14b of the annular wall portion 14, and 30 denotes the stator core 28.
The stator coil 32 wound around the rotor hub 24
The rotor magnet is fixed inside the peripheral wall 34 and faces the stator core 28 with a circumferential gap.

The open end 34 of the peripheral wall 34 of the rotor hub 24
a is in a state of being inserted into the annular recess 12 up to the vicinity of the bottom thereof, and the outwardly extending portion 36 provided in the middle portion of the peripheral wall 34 is the enlarged diameter portion provided in the opening of the annular recess 12. 1
It is in a state that it is fitted in 6. Then, the rotor magnet 32, the rotor hub 24, and the outward protruding portion 36,
A labyrinth seal effect is obtained by the annular concave portion 12 and the enlarged diameter portion 16 thereof, and it is possible to prevent oil fine particles and dust from scattering in the disk chamber 11.

A first magnetic disk 38 is externally fitted onto the outwardly projecting portion 36 on the outer peripheral portion of the rotor hub 24, and an annular spacer 40 is mounted on the first magnetic disk 38. 40 on the second magnetic disk 4
2 is externally fitted.

Reference numeral 44 denotes the first and second magnetic disks 38.
And 42 are fixed clamp members. The clamp member 44 is fitted to the end surface portion of the rotor hub 24,
It is screwed on.

Reference numeral 46 denotes an annular wall portion 14 which is a through portion.
A sealing member for sealing the inner peripheral portion of the lower end portion in FIG.
Reference numeral 48 is a rubber ball that closes one end of the hollow portion of the shaft member 26.

The above annular recess 12, annular wall 14 and first
Bearing 18, second bearing 20, rotor hub 24, stator core 28, stator coil 30, rotor magnet 3
A spindle motor A for driving the magnetic disk is constituted by 2 and the like. Since the annular recess 12 of the spindle motor A is provided integrally with the substrate 10, the height of the entire device can be suppressed low.

A circular recess 50 is provided slightly to the left of the base 10 in FIG. 1, and the circular recess 50 is provided.
The base portion 52a of the fixed shaft 52 is fitted and fixed to. A rotary sleeve member 58 is rotatably supported by the fixed shaft 52 via a third bearing 54 and a fourth bearing 56.

Reference numeral 60 is an arm member projecting from the rotary sleeve member 58 toward the first and second magnetic disks 38 and 42, and 62 is a magnetic head provided at the tip of the arm member 60. This magnetic head 62 has a first
And the second magnetic disks 38 and 42, respectively.

Reference numeral 64 denotes a movable coil fixed to the side of the rotary sleeve member 58 opposite to the arm member 60.

Reference numeral 66 is a first yoke, and 68 is a second yoke. The first yoke 66 is screwed to the end of the fixed shaft 52, and the second yoke 68 is fitted to the fixed shaft 52.

A pair of substantially fan-shaped permanent magnet plates 74 are fixed to the facing surfaces of the first yoke 66 and the second yoke 68, respectively. As this permanent magnet plate 74, Nd-Fe is used.
It is desirable to use a -B type magnet.

The fixed shaft 52, the third bearing 54, the fourth
Bearing 56, rotating sleeve member 58, moving coil 64,
First yoke 66, second yoke 68, permanent magnet plate 74
Configure a voice coil motor B for rotating the arm member 60 to move and position the magnetic head 62.

Reference numeral 76 denotes a lid of the disc chamber 11,
It has a box shape. The spindle motor A, the first and second magnetic disks 38 and 42, the voice coil motor B, the arm member 60, the magnetic head 62, etc. are provided in the disk chamber 11 formed by attaching the lid 76 to the base 10. Is sealed.

Reference numeral 78 is a center-of-gravity adjusting member for moving the position of the center of gravity on the base. The center-of-gravity adjusting member 78 is made of aluminum, which is the same material as the base 10,
It is provided on the lower surface of the base 10 so as to fill the gap portion provided in the lower portion of the base 10 at a position symmetrical to the mounting position of the voice coil motor B with respect to the shaft center of the shaft member 26.

Further, in a portion of the disk chamber 11 where the first and second magnetic disks 38 and 42 do not exist, the upper center of gravity adjusting member is provided on the upper surface of the base 10 on the end side where the aforementioned center of gravity adjusting member 78 is provided. 79 are attached.

Center of gravity adjusting member 78 and upper center of gravity adjusting member 7
9 are concentratedly provided on one end face side with respect to the shaft center of the shaft member 26 in the spindle motor A, and are balanced with the moment on the other end portion side where the base plate area is relatively large. The center of gravity of is substantially coincident with the axis of the shaft member 26 of the spindle motor A. Further, if the side-by-side amount and the side-by-side position for making the center of gravity of the base 10 and the shaft center of the shaft member 26 in the spindle motor A substantially coincide with each other become clear, the center-of-gravity adjusting member 78 and the upper center-of-gravity adjusting member 79 are integrated with the base 10. It is also possible to form them as desired.

FIG. 3 is a perspective view showing a base of a magnetic disk drive device according to another embodiment of the present invention.

Reference numeral 103 is a base of the magnetic disk drive having a substantially rectangular shape, and 100 is a base 103 in which a bearing or a bearing fixing member is fixed to an annular wall portion (not shown) formed integrally with the base 103. It is a spindle motor having a hub that is rotatable relative to. Reference numeral 101 denotes a mounting hole for a fixed shaft that pivotally supports a head and an arm member that supports the head for writing and / or reading information on the magnetic disk mounted on the hub. Reference numeral 102 is a voice coil motor mounting hole for rotating the head and arm members in the radial direction of the magnetic disk. The base 103 is entirely formed of a flat aluminum plate, and has a voice coil motor mounting hole 102 and a fixed shaft mounting hole 101 at one end and a spindle motor 100 at the center.

Since the base 103 having the above structure is thin as a whole, there is little space for installing the center-of-gravity adjusting member as in the first embodiment, and the center-of-gravity adjusting member is used for the shaft member of the spindle motor 100. It is difficult to match the axis center with the center of gravity of the base 103. Therefore, although the magnetic disk drive is slightly enlarged, one end surface of the base 103 is extended outward so that the shaft center of the shaft member of the spindle motor 100 is located substantially in the center of the base 103. The center of gravity of 103 was matched.

Although the embodiment of the magnetic disk drive according to the present invention has been described above, the present invention is not limited to this embodiment and various modifications and corrections can be made.

For example, in the first embodiment, the substrate 1
The center-of-gravity adjusting member 78 and / or the upper center-of-gravity adjusting member 79 attached to 0 is not limited to the same material as that of the substrate 10, and if a metal such as lead having a large specific gravity is used, the amount of the attached center can be small, and the second implementation In a magnetic disk drive device with a small space as in the example, if the extension width of the base is set a little and a center of gravity adjusting member is installed in the extension of the base where the magnetic disk does not exist, the spindle motor will not be enlarged. It is also possible to make the axis center of the shaft member and the center of gravity of the base coincide with each other.

Further, when the substrate is formed, a center of gravity adjusting member is integrally formed on the outside of the substrate, the spindle motor is assembled, and then the center of gravity adjusting member is cut. It is possible to manufacture a motor that is the same as the above, and has less shaft eccentricity. Therefore, it can be sufficiently applied to a small and thin magnetic disk drive.

[0038]

In the magnetic disk drive of the present invention, since the center of gravity of the base and the shaft center of the shaft member in the spindle motor are substantially coincident with each other, the base is fixed and an annular member provided on the base is provided. When assembling the shaft member and the bearing or the bearing fixing member of the spindle motor by applying pressure, the pressure can be evenly applied, the axial direction of the annular member and the axial direction of the shaft member become constant, and the eccentricity of the shaft member It is possible to easily provide a magnetic disk drive device equipped with a spindle motor without a magnetic disk.

[Brief description of drawings]

FIG. 1 is a plan view of a magnetic disk drive device of the present invention.

FIG. 2 is a side view of the magnetic disk drive device in FIG.

FIG. 3 is a perspective view of a magnetic disk drive device according to another embodiment.

[Explanation of symbols]

 A spindle motor B voice coil motor 10 base 11 disk chamber 14 annular wall portion 18 first bearing 20 second bearing 24 rotor hub 26 shaft member 78 center of gravity adjusting member 79 upper center of gravity adjusting member

Claims (3)

[Claims] 1. A rotor hub comprising a base for defining a disk chamber and a magnetic disk driving spindle motor mounted on the base, the spindle motor being rotatable relative to a shaft member and the shaft member. And a bearing or a bearing fixing member arranged between the shaft member and the rotor hub,
In a magnetic disk drive in which the base and an annular wall portion for fixedly supporting the bearing or the bearing fixing member of the spindle motor are integrally formed, a shaft member of the spindle motor of the spindle motor is assembled when the spindle motor is assembled. A magnetic disk drive, wherein an axis and a center of gravity of the base are substantially coincident with each other. 2. A center of gravity of the base of the magnetic disk drive is attached to one end of the base of the magnetic disk drive so that the center of gravity of the base substantially coincides with the axis of a shaft member of a spindle motor for driving the magnetic disk. 2. The magnetic disk drive device according to claim 1, wherein 3. A magnetic disk drive device has one end of the base extending outward so that the center of gravity of the base substantially coincides with the axis of a shaft member of a spindle motor for driving the magnetic disk. The magnetic disk drive device according to claim 1.