JP2002374650A - Magnetic disc drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable magnetic disc drive having a high recording density whose manufacturing cost can be reduced by decreasing the number of components and the labor of assembling work and the precision in radial wobbling of a motor is enhanced. SOLUTION: The magnetic disc drive comprises an outer rotor motor a spindle shaft 5 comprising a two stage shaft having a large diameter section and a small diameter section and disposed in a sleeve 10 of a ball bearing body, and a ball bearing body comprising balls 14 provided between the outer circumferential surface of an inner ring 8 disposed at the small diameter section and the sleeve and balls 13 provided between the large diameter section and the sleeve wherein the large diameter section is connected with a motor component, i.e., a rotor 9, and formed integrally of the same material, the sleeve is secured to the center of a base 1a, a stator yoke 4 is provided on the outer circumference of the sleeve and disposed oppositely to the inner circumferential surface of a magnet 15 provided on the inner circumferential surface of the rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The magnetic disk drive of the present invention is mainly used for OA equipment.

[0002]

2. Description of the Related Art As a motor of a magnetic disk drive, for example, a spindle motor is used. As shown in FIG. 10, the motor has a spindle shaft, a rotor (rotor yoke),
A yoke holder is provided, and the spindle shaft is supported by ball bearings including inner and outer rings provided in a sleeve of the bearing main body. Each of these components is configured as an independent unit.

[0003]

As described above, the conventional motor of the magnetic disk drive has a large number of components because each component is independently configured as a single component. There is a drawback in that a mutual assembling process of the parts is required, the number of manufacturing steps is increased, and the manufacturing cost is high.

According to the present invention, by integrally forming a part of a motor part and a part of a bearing, the number of parts and the number of assembling steps are reduced, the production cost can be reduced, and the shaft runout accuracy of the motor can be reduced. Therefore, it is an object of the present invention to provide a magnetic disk device having high recording density and excellent reliability.

[0005]

In order to achieve the above object, a magnetic disk drive according to a first aspect of the present invention is characterized in that a spindle shaft composed of a two-stage shaft having a large-diameter portion and a small-diameter portion has a ball bearing main body. An inner ring is provided in a small diameter portion of the spindle shaft provided in a sleeve, and a plurality of balls are provided between a rolling groove formed on an outer peripheral surface of the inner ring and a rolling groove formed on an inner peripheral surface of the sleeve. The sleeve of the ball bearing body, wherein a plurality of balls are provided between a rolling groove formed on an outer peripheral surface of a large diameter portion of the spindle shaft and a rolling groove formed on an inner peripheral surface of the sleeve. And a rotor which is a motor component integrally formed of the same material.

In a magnetic disk drive according to a second aspect of the present invention, a spindle shaft comprising a two-stage shaft having a large-diameter portion and a small-diameter portion is provided in a sleeve of a ball bearing body, and an inner ring is provided at the small-diameter portion of the spindle shaft. A plurality of balls are provided between a rolling groove formed on an outer peripheral surface of the inner ring and a rolling groove formed on an inner peripheral surface of the sleeve, and an outer peripheral surface of a large diameter portion of the spindle shaft is provided. A large diameter portion of the spindle shaft of a ball bearing body provided with a plurality of balls between a rolling groove formed on the inner peripheral surface of the sleeve and a rolling groove formed on the inner peripheral surface of the sleeve is connected to a rotor as a motor component, In addition, the motor includes a motor integrally formed of the same material.

According to a third aspect of the present invention, there is provided a magnetic disk drive, wherein a spindle shaft comprising a two-stage shaft having a large diameter portion and a small diameter portion is provided in a sleeve of a ball bearing body, and an inner ring is provided at the small diameter portion of the spindle shaft. A plurality of balls are provided between a rolling groove formed on an outer peripheral surface of the inner ring and a rolling groove formed on an inner peripheral surface of the sleeve, and an outer peripheral surface of a large diameter portion of the spindle shaft is provided. And the sleeve of the ball bearing body, in which a plurality of balls are provided between the rolling groove formed on the inner peripheral surface of the sleeve and the rolling groove formed on the inner surface of the sleeve, is integrally formed of the same material as a yoke holder as a motor component. This is a configuration having a motor.

In a magnetic disk drive according to a fourth aspect of the present invention, a spindle shaft comprising a two-stage shaft having a large-diameter portion and a small-diameter portion is provided in a sleeve of a ball bearing body, and an inner ring is provided at the small-diameter portion of the spindle shaft. A plurality of balls are provided between a rolling groove formed on an outer peripheral surface of the inner ring and a rolling groove formed on an inner peripheral surface of the sleeve, and an outer peripheral surface of a large diameter portion of the spindle shaft is provided. The spindle shaft of the ball bearing body having a plurality of balls provided between the rolling groove formed on the inner peripheral surface of the sleeve and the rolling groove formed on the yoke holder, which is a motor component, is connected to the same material. And an integrated motor.

In a magnetic disk drive according to a fifth aspect of the present invention, a spindle shaft comprising a two-stage shaft having a large-diameter portion and a small-diameter portion is provided in a sleeve of a ball bearing body, and an inner ring is provided at the small-diameter portion of the spindle shaft. A plurality of balls are provided between a rolling groove formed on an outer peripheral surface of the inner ring and a rolling groove formed on an inner surface of the sleeve, and formed on an outer peripheral surface of a large diameter portion of the spindle shaft. The inner ring of the ball bearing body having a plurality of balls provided between the rolling groove formed and the rolling groove formed on the inner peripheral surface of the sleeve is connected to a yoke holder as a motor component, and integrally formed of the same material. This is a configuration including the configured motor.

[0010]

In the magnetic disk drive according to the present invention, the rotor and the yoke holder, which are members of the motor, are integrally formed with the sleeve, the spindle shaft or the inner ring of the bearing main body. The number of parts is smaller than that of the product, and the man-hour for assembling at the time of manufacture is small.

In the magnetic disk drive of the present invention, the spindle shaft has a two-stage shaft structure having a large-diameter portion and a small-diameter portion, and the inner ring is provided in the small-diameter portion. The spindle shaft can be made large as a whole without reducing the diameter of the ball, and the rigidity of the shaft is improved.

Further, since the assembled motor has a small shaft runout and is thermally stable, the track density of the magnetic disk can be increased, and the surface runout is small, so that the flying height of the head is low. The recording density can be set, and the linear recording density can be increased. As a result, the recording density of the magnetic disk device can be improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the magnetic disk drive according to the present invention will be described below with reference to specific examples shown in the accompanying drawings. 1 and 2
Shows an embodiment in which an outer rotor type spindle motor is used in the magnetic disk drive according to the present invention.

In FIGS. 1 and 2, reference numeral 1 denotes a casing of a magnetic disk drive. The casing is provided with an outer rotor type spindle motor M according to an original creation of the applicant company. This motor has the following structure. There is.

That is, the base 1a of the casing 1
Is provided with a bottomed cylindrical yoke holder 2, and a stator yoke 4 having a coil 3 is provided around the yoke holder.

At the center of the bottom of the yoke holder 2, a lower portion of a spindle shaft 5 is fixed, and the upper portion of the spindle shaft is a two-stage shaft having a small diameter. A rolling groove 6 is formed on the outer periphery of the lower large-diameter portion of the spindle shaft, and an inner ring 8 having a rolling groove 7 formed on the outer periphery is fitted on the small-diameter portion.

A sleeve 10 of a ball bearing body is formed integrally with the rotor on the lower surface at the center of the rotor 9 serving as an outer rotor, and the inner surface of the rotor 9 has a large-diameter portion rolling groove of the spindle shaft and a rolling groove of the inner ring. Corresponding double rows of rolling grooves 11 and 12 are formed, and the ball 1 is inserted between the corresponding rolling grooves.
3 and 14, the sleeve 10, the ball 1
The ball bearing main body is constituted by 3 and 14, the inner race 7 and the rolling groove 6 of the large diameter portion. The ball bearing main body is held by this so that the rotor can rotate around the spindle axis. And a magnet provided on the inner surface of the outer peripheral flange of the rotor in correspondence with the above.

In the embodiment shown in FIG. 3, a sleeve 10 of a ball bearing body is provided at the center of a base 1a of a casing 1, and a spindle shaft 5 is integrally provided on a lower surface of a center portion of a rotor 9. Is a two-stage shaft, but only the vertical direction is opposite to that of FIG. 2 and the rolling groove 6 of the spindle shaft, the inner ring 8 and its rolling groove 7, the rolling grooves 11 and 12 of the sleeve, The mutual structural relationship between the balls 13 and 14 is the same as that of FIG. In this embodiment, the stator yoke 4 is mounted around the sleeve 10, so that a configuration corresponding to the yoke holder 2 in FIG. 2 is not required.

FIGS. 4 and 5 show examples in which an inner rotor type spindle motor is used as a motor. The one in FIG.
A spindle shaft 5 consisting of a two-stage shaft is provided upright at the center of the bottom of the yoke holder 2, and a stator yoke 4 is mounted on the inner peripheral surface of a rising cylindrical rib 2a of the yoke holder. In this embodiment, the sleeve 10 of the ball bearing body is used.
Is formed integrally with the rotor on the lower surface at the center of the rotor 9,
The structure of the ball bearing body is the same as that of the embodiment of FIG. 2, but the magnet is provided on the outer periphery of the sleeve 10.

In FIG. 5, the yoke holder 2 of the ball bearing body is integrally formed with the sleeve 10 of the ball bearing body, and the spindle shaft 5 and the rotor 9 are integrally formed.
The stator yoke 4 is provided on the inner circumferential surface of the rising cylindrical rib 2 a of the yoke holder 2, and the magnet 15 is provided on the outer circumference of a cylindrical magnet holder 16 integrally formed on the lower surface of the center of the rotor 9. So, use a two-stage spindle for the spindle,
The ball bearing body has the same structure as the embodiment of FIG.

Reference numeral 18 denotes a magnetic disk mounted on the rotor, 19 denotes a magnetic head provided on the lower surface of the tip of a head arm 20, and 21 denotes an upper cover of the apparatus.

In addition to the above embodiment, there are many variations in which the rotor and the yoke holder, which are members of the motor, are formed integrally with the sleeve, the spindle shaft or the inner ring of the ball bearing body, and one example thereof will be briefly described below.

FIG. 6 shows the rotor 9 and the sleeve 1 of the ball bearing body.
FIG. 7 shows the yoke holder 2 integrated with the sleeve 10 of the ball bearing body, FIG. 8 shows the yoke holder 2 integrated with the inner ring 8 of the ball bearing body, and FIG. An example in which they are formed integrally is shown.

[0024]

According to the motor used in the apparatus of the present invention, the rotor and the yoke holder which are members of the motor are formed integrally with the sleeve, the spindle shaft or the inner ring of the bearing body, so that the rotor and the yoke holder are formed separately from the bearing body. Unlike the prior art, there is a great advantage in industrial production that the assembling at the time of manufacturing is easy, the assembling by a machine can be performed efficiently, and the manufacturing cost can be reduced.

Further, since any of the motor components such as the rotor and the yoke holder are formed integrally with the sleeve of the ball bearing body, the spindle shaft or the inner ring in advance, the motor is aligned with the spindle shaft at the time of manufacture. Are unnecessary, the shaft runout is small, and the rotation accuracy is high.

Further, the spindle shaft in the magnetic disk drive of the present invention has a two-stage shaft structure having a large diameter portion and a small diameter portion, and the inner ring is provided in the small diameter portion, so that the thickness of the inner ring can be reduced. The spindle shaft can be made large as a whole without reducing the diameter of the ball, and the rigidity of the shaft can be improved.

Therefore, according to the present invention, the main part of the motor is an integral part of a part of the bearing main body, which reduces the shaft runout and is thermally stable. The reliability of data transfer is improved, and the track density of the magnetic disk can be increased,
In addition, since the surface deflection of the magnetic disk is small, the flying height of the magnetic head can be set low, and the linear recording density can be increased. As a result, a magnetic disk device with high recording density and excellent reliability can be provided.

In the bearing body of the device according to the first to fourth aspects of the present invention, the preload can be applied to the inner race fitted to the small diameter portion of the two-stage shaft by applying a pressure from the axial direction thereof, so that the preload can be properly performed. There is a manufacturing advantage that it can be easily hung.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view showing a first embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing a third embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing a fourth embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a fifth embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing a sixth embodiment of the present invention.

FIG. 8 is a longitudinal sectional view showing a seventh embodiment of the present invention.

FIG. 9 is a longitudinal sectional view showing an eighth embodiment of the present invention.

FIG. 10 is a partial longitudinal sectional view showing a conventional spindle motor.

[Explanation of symbols]

 Reference Signs List 1 casing 1a base 2 yoke holder 2a tubular rib 3 coil 4 stator yoke 5 spindle shaft 6, 7 rolling groove 8 inner ring 9 rotor 10 sleeve 11, 12 rolling groove 13, 14 ball 15 magnet 16 magnet holder 17 outer ring 18 magnetic disk 19 Magnetic Head 20 Head Arm 21 Top Cover M Motor

[Procedure amendment]

[Submission date] April 1, 2002 (2002.4.1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Magnetic disk drive

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The magnetic disk drive of the present invention is mainly used for OA equipment.

[0002]

2. Description of the Related Art As a motor of a magnetic disk drive, for example, a spindle motor is used . As shown in FIG. 4 , the motor includes a spindle shaft, a rotor (rotor yoke), and a yoke holder. These parts are supported by ball bearings formed of inner and outer rings provided in a sleeve of the main body, and these parts are formed as independent single parts.

[0003]

As described above, the conventional motor of the magnetic disk drive has a large number of components because each component is independently configured as a single component. There is a drawback in that a mutual assembling process of the parts is required, the number of manufacturing steps is increased, and the manufacturing cost is high.

The present invention reduces the number of parts and the number of assembly steps by integrally forming a rotor as a part of a motor part and a spindle shaft as a part of a bearing, thereby reducing manufacturing costs. It is another object of the present invention to provide a magnetic disk device having a high recording density and excellent reliability by improving the shaft runout accuracy of a motor.

[0005]

In order to achieve the above object, a magnetic disk drive according to the present invention comprises a spindle shaft having a two-stage shaft having a large-diameter portion and a small-diameter portion provided in a sleeve of a ball bearing body. An inner ring is provided at a small diameter portion of the spindle shaft, and a plurality of balls are provided between a rolling groove formed on an outer peripheral surface of the inner ring and a rolling groove formed on an inner peripheral surface of the sleeve; comprising a ball bearing body formed by a plurality of balls between the grooves formed on the inner peripheral surface of the rolling groove and the sleeve which is formed on the outer peripheral surface of the large diameter portion of the spindle shaft, the spindle shaft The large-diameter portion is connected to the rotor as a motor component, and is integrally formed of the same material.
Fix the sleeve, and install a coil around the outer circumference of this sleeve.
The stator yoke is provided on the inner peripheral surface of the rotor.
And an outer rotor type motor facing the inner peripheral surface of the magnet .

[0006]

In the magnetic disk drive according to the present invention, the rotor as a member of the motor is formed integrally with the spindle shaft of the bearing main body. In addition, the number of assembling man-hours during production can be reduced.

[0007] The spindle shaft in the magnetic disk device of the present invention a two-stage shaft structure having a large diameter portion and a small diameter portion, than has a configuration provided with inner small-diameter portion, or the wall thickness of the inner ring, Alternatively, the spindle shaft can be made to have a large diameter without reducing the diameter of the ball, thereby improving the rigidity of the shaft.

Furthermore, braided motor less axial runout, and because it is also stable thermally, it is possible to increase the track density of the magnetic disk, and since surface vibration is small, the flying height of the head is low The recording density can be set, and the linear recording density can be increased. As a result, the recording density of the magnetic disk device can be improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic disk drive according to the present invention will be described below with reference to a specific example shown in the accompanying drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a casing of a magnetic disk drive. The casing is provided with an outer rotor type spindle motor according to an original creation of the applicant company. The motor has the following structure. is there.

[0011] That is, the base 1a of the casing 1
Yes Said sleeve 10 of the ball bearing body is provided in a central portion, Sri
A stator yoke 4 with a coil 3
Is provided.

On the lower surface of the center of the rotor 9 as the outer rotor
Is integrally provided with a spindle shaft 5, which is a two-stage shaft having a large diameter at the upper part and a small diameter at the lower part . A rolling groove 6 is formed on the outer periphery of the upper large diameter portion of the spindle shaft, and an inner ring 8 having a rolling groove 7 formed on the outer periphery is fitted on the small diameter portion.

The inner surface of the sleeve 10 has a plurality of rows of rolling grooves 11 and 12 corresponding to the large diameter rolling grooves of the spindle shaft and the inner ring. By providing the balls 13 and 14 between them, the ball bearing body is constituted by the sleeve 10, the balls 13 and 14, the inner ring 8 and the rolling groove 6 of the large diameter portion, so that the rotor can rotate around the spindle axis. Reference numeral 15 in the drawing denotes a magnet provided on the inner surface of the outer peripheral flange of the rotor in correspondence with the stator yoke.

Reference numeral 18 denotes a magnetic disk mounted on the rotor, 19 denotes a magnetic head provided on the lower surface of the tip of a head arm 20, and 21 denotes an upper cover of the apparatus.

[0015]

The motor used in the apparatus of the present invention differs from the conventional motor in which the rotor, which is a member of the motor, is formed integrally with the spindle shaft of the bearing body, and the rotor is formed separately from the bearing body. In addition, there is a great advantage in industrial production that the assembling at the time of manufacturing is easy, the assembling by a machine can be performed efficiently, and the manufacturing cost can be reduced.

Further , since the rotor, which is a motor component , is formed integrally with the spindle shaft of the ball bearing body in advance, the motor does not require centering of the spindle shaft with respect to the component at the time of manufacture, and the motor has less shaft runout. , The rotation accuracy is high.

Furthermore, the spindle axis in the magnetic disk device of the present invention is a two-stage shaft structure having a large diameter portion and a small diameter portion, in which a configuration in which the inner ring diameter portion, or the wall thickness of the inner ring, or The spindle shaft can be made large as a whole without reducing the diameter of the ball, and the rigidity of the shaft can be improved.

[0018] Thus, according to the present invention, since the main part of the motor is stable even in they become an integral part and a part of the bearing body less axial runout, and thermal, between the magnetic disk and the magnetic head The reliability of data transfer is improved, and the track density of the magnetic disk can be increased,
In addition, since the surface deflection of the magnetic disk is small, the flying height of the magnetic head can be set low, and the linear recording density can be increased. As a result, a magnetic disk device with high recording density and excellent reliability can be provided.

Further, in the bearing body of the device according to the present invention, the inner ring fitted to the small diameter portion of the two-stage shaft can be preloaded by applying pressure from the axial direction thereof, so that the preload can be appropriately and easily applied. There is an advantage in production.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of the motor according to the embodiment of the present invention.

FIG. 4 is a partial longitudinal sectional view showing a conventional spindle motor.

DESCRIPTION OF REFERENCE NUMERALS 1 casing 1a base 2 yoke holder 3 coil 4 stator yoke 5 spindle shaft 6, 7 rolling groove 8 inner ring 9 rotor 10 sleeve 11, 12 rolling groove 13, 14 ball 15 magnet 18 magnetic disk 19 magnetic head 20 Head arm 21 top lid

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG. 2

FIG.

FIG. 3

FIG. 4

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) H02K 7/14 H02K 7/14 CF term (Reference) 3J101 AA02 AA43 AA54 AA62 BA01 BA53 BA54 BA56 BA65 BA77 FA15 FA41 FA44 GA53 5D109 BA03 BA13 BA17 BA20 BB03 BB16 5H605 AA07 AA08 BB05 BB10 BB14 BB19 CC04 DD09 EA19 EB04 EB10 EB16 5H607 AA12 BB01 BB07 BB14 BB17 BB25 CC09 DD05 DD08 FF12 GG04 GG08

Claims (5)

[Claims] 1. A spindle shaft comprising a two-stage shaft having a large-diameter portion and a small-diameter portion is provided in a sleeve of a ball bearing body, and an inner ring is provided on the small-diameter portion of the spindle shaft and formed on an outer peripheral surface of the inner ring. A plurality of balls are provided between the rolling groove formed on the inner peripheral surface of the sleeve and the rolling groove formed on the inner peripheral surface of the sleeve. A magnetic disk drive comprising a motor in which the sleeve of a ball bearing main body having a plurality of balls provided between rolling grooves formed on a peripheral surface and a rotor as a motor component are integrally formed of the same material. 2. A spindle shaft comprising a two-stage shaft having a large-diameter portion and a small-diameter portion is provided in a sleeve of a ball bearing body, and an inner ring is provided on the small-diameter portion of the spindle shaft and formed on an outer peripheral surface of the inner ring. A plurality of balls are provided between the rolling groove formed on the inner peripheral surface of the sleeve and the rolling groove formed on the inner peripheral surface of the sleeve. A motor in which a large diameter portion of the spindle shaft of a ball bearing body provided with a plurality of balls between rolling grooves formed on a peripheral surface is connected to a rotor serving as a motor component, and is integrally formed of the same material. A magnetic disk drive provided. 3. A spindle shaft comprising a two-stage shaft having a large-diameter portion and a small-diameter portion is provided in a sleeve of the ball bearing body, and an inner ring is provided on the small-diameter portion of the spindle shaft and formed on an outer peripheral surface of the inner ring. A plurality of balls are provided between the rolling groove formed on the inner peripheral surface of the sleeve and the rolling groove formed on the inner peripheral surface of the sleeve. A magnetic disk drive comprising a motor in which the sleeve of a ball bearing main body having a plurality of balls provided between rolling grooves formed in a peripheral surface and a yoke holder as a motor component is integrally formed of the same material. 4. A spindle shaft comprising a two-stage shaft having a large-diameter portion and a small-diameter portion is provided in a sleeve of the ball bearing body, and an inner ring is provided on the small-diameter portion of the spindle shaft and formed on an outer peripheral surface of the inner ring. A plurality of balls are provided between the rolling groove formed on the inner peripheral surface of the sleeve and the rolling groove formed on the inner peripheral surface of the sleeve. A magnet comprising a motor in which the spindle shaft of a ball bearing body having a plurality of balls provided between the rolling grooves formed on the peripheral surface is connected to a yoke holder as a motor component and is integrally formed of the same material. Disk device. 5. A spindle shaft comprising a two-stage shaft having a large-diameter portion and a small-diameter portion is provided in a sleeve of a ball bearing body, and an inner ring is provided on the small-diameter portion of the spindle shaft and formed on an outer peripheral surface of the inner ring. A plurality of balls are provided between the rolling groove formed on the inner surface of the sleeve and the rolling groove formed on the outer peripheral surface of the large diameter portion of the spindle shaft. A magnetic disk drive comprising a motor in which the inner ring of a ball bearing main body having a plurality of balls provided between the rolling grooves formed in the above-mentioned section is connected to a yoke holder as a motor component and is integrally formed of the same material.