JP2003304664A - Spindle motor, its manufacturing method, and recording disk driver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably hold a rotating member by raising the accuracy of the inside periphery face of the sleeve of a spindle motor. <P>SOLUTION: The method of manufacturing a spindle motor 1 is applied to an object having the following structure. A radial bearing 35 is constituted, which rotatably supports the rotating member 3 to a static member 2 by a gas retained in a small aperture located between the outside periphery face 10 of a sleeve on fixing side and the inside periphery face 14b of the sleeve 14 on rotation side. A flange 13d for supporting a disc 83 and a spacer 91 in the axial direction is made at the outside periphery face of a hub 13. In the hub, the inside periphery of the flange keeps space to the outside periphery 14a of the sleeve on the rotation side. This manufacturing method possesses the following processes a process of setting the hub 13 and the sleeve 14 on rotation side; a process of polishing the inside periphery face 14b of the sleeve on rotation side, after setting of the hub 13 and the sleeve 14 on rotation side; and a process of assembling the rotating member 3 after polishing and the static member. <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 spindle motor, and more particularly to a rotary member which constitutes a gas radial dynamic pressure bearing portion and on which a load is mounted, and the rotary member is fitted to the sleeve and the outer peripheral surface thereof. And a spindle motor including a hub. The present invention further relates to a method of manufacturing the spindle motor, and a recording disk drive device using the spindle motor.

[0002]

2. Description of the Related Art For example, a hard disk drive as a recording disk drive includes a device housing defining a housing chamber, a spindle motor mounted on the device housing, a magnetic recording disk mounted on the spindle motor, and a recording disk. And a magnetic head for writing the recording information and / or reading the recording information. In recent years, the amount of programs and data handled by this hard disk drive has increased, increasing the storage capacity of the hard disk drive and increasing the speed of writing / reading recorded information are increasingly demanded. As a result, the precision of spindle motors is increasing. Along with this increase in precision, the bearing means for rotatably supporting the spindle motor is about to be replaced with a dynamic pressure bearing. In a dynamic pressure bearing, a minute gap is formed between relatively rotating members, and the lubricating fluid held in this gap generates dynamic pressure due to relative rotation of the members, so that one member (static member) On the other hand, the other member (rotating member) is rotatably supported in a non-contact manner. Generally, liquid or gas is used as a lubricating fluid, and the radial bearing part that supports the radial direction of the rotating member and the rotating member. It is composed of a thrust bearing portion that supports the thrust direction of the member. When such a dynamic pressure bearing is adopted, it can rotate with lower noise and higher accuracy than a ball bearing.

However, it is expected that the amount of programs and the amount of data will further increase in the near future, and along with this, the rotation speed of the spindle motor is required to be high-speed rotation of 20000 rpm or more. With such high speed rotation, when oil is used as the lubricating fluid, the axial loss during rotation increases due to the viscous resistance of the oil, making it difficult to support high speed rotation of 20000 rpm or higher. In addition, the viscous characteristic of oil greatly changes depending on temperature, and it becomes difficult to stably and rotatably support the hub in an environment where the ambient temperature changes greatly.

Therefore, in order to cope with a further high speed rotation, it is considered to employ a gas dynamic pressure bearing which uses air as a lubricating fluid. When gas is used as the lubricating fluid, the viscous resistance is much smaller than that of oil (the viscous resistance of gas is about 1/1000 of the viscous resistance of oil), so the axial loss during rotation is small and the temperature The viscosity specification does not change significantly even if the value changes, and the rotor hub can be stably rotatably supported at high speed.

Japanese Unexamined Patent Publication No. 2001-146915 discloses that
A dynamic pressure bearing using gas as a lubricating fluid for a radial bearing portion is disclosed. In this dynamic pressure bearing, the rotating member includes a hub and a rotating sleeve fitted and fixed to the inner peripheral surface of the hub. A recording disk is mounted on the outer peripheral surface of the hub, and the inner peripheral surface of the rotating-side sleeve is radially opposed to the outer peripheral surface of the fixed-side sleeve with a minute gap. Gas is filled in the minute gap, which constitutes the gas radial bearing part. The reason why the rotary member is divided into the hub and the sleeve is that the rotary member has a function of mounting a load and a radial bearing. This is because the function of forming the surface is required, and it is preferable to combine different members in order to realize these different functions. In particular,
Since the radial bearing surface is required to have slidability and wear resistance, ceramic is used as a suitable material for the rotary sleeve. On the other hand, it is necessary to make the positioning and the like highly accurate in the portion where the mounted object is mounted, and a metal such as aluminum or stainless steel is used for the hub as a material suitable for this in view of cutting.

[0006]

In the structure in which the rotary member is composed of the hub and the sleeve, the following problems have been pointed out regarding the accuracy of the inner peripheral surface of the sleeve, which is the bearing surface. A mounted object such as a recording disk is fitted to the outer peripheral surface of the hub and supported by the mounting portion, and is clamped and fixed between the mounting portion and the mounting portion. The load from this mounted object may act in the inner diameter direction via the mounted portion and may be transmitted to the sleeve, which may deform the inner peripheral surface.

Deformation due to the load from the mounted object can be prevented by providing a gap between the hub and the sleeve and in the vicinity of the mounted portion, as shown in FIG. 3 of JP 2001-146915 A, for example. . However, in the structure of FIG. 3, this gap needs to be formed on the sleeve outer peripheral surface corresponding to the sleeve inner peripheral surface that functions as a bearing surface. For this reason, the close contact portion where the sleeve and the hub are fastened needs to be provided in the bearing portion so as to be displaced in the axial direction. As a result, the size of the inner peripheral surface of the sleeve is restricted and the bearing portion becomes smaller, and sufficient bearing rigidity cannot be obtained, or because the bearing portion is made larger, the close contact portion becomes smaller and the hub and sleeve cannot be fastened together. Insufficient, and due to the fact that the bearing part and the close contact part were sufficiently secured in the sleeve, there was a restriction such that the axial dimension of the spindle motor became large, and there was no freedom in design, and various requests were met. There is a problem that you cannot do it.

In the spindle motor as described above, if the inner peripheral surface of the sleeve is deformed, the desired bearing capacity cannot be exerted, and the rotating member cannot be stably held (that is, high precision can be achieved). Can not). Further, when a spindle motor adopting such a dynamic pressure bearing is used in a recording disk drive device such as a hard disk, it is impossible to increase the recording density of the recording disk, and it is impossible to increase the capacity. Can not correspond to.

An object of the present invention is to provide a spindle motor which comprises a sleeve and a hub fitted to the outer peripheral surface of a rotary member, which constitutes a gas radial dynamic pressure bearing portion and on which a mounting portion is mounted, in a spindle motor. The object is to improve the accuracy of the inner peripheral surface of the sleeve without increasing the size and to stably hold the rotating member.

[0010]

A spindle motor according to a first aspect of the present invention comprises a stationary member, a rotating member, a stator coil, and a rotor magnet. The stationary member has a shaft. The rotating member has a cylindrical shape in which a sleeve having a through hole through which a shaft is inserted through a minute gap is formed, and an outer peripheral surface of the sleeve is closely fitted to an inner peripheral surface of the sleeve and a mounting object is mounted on the outer peripheral surface thereof. And a hub. The stator is fixed to the stationary member. The rotor magnet is fixed to the hub so as to face the stator and cooperates with the stator to generate a rotating magnetic field. A minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and the gas held in the minute gap constitute a radial dynamic pressure bearing portion that rotatably supports the rotating member with respect to the stationary member. . On the outer peripheral surface of the hub, a mounting portion that supports the mounted object in the axial direction is formed. The inner peripheral surface of the portion of the hub where the mounting portion is provided secures a gap between the inner peripheral surface and the outer peripheral surface of the sleeve. This gap can be formed by removing at least one of the hub inner peripheral surface and the sleeve outer peripheral surface. The inner peripheral surface of the sleeve is ground after the sleeve and the hub are fitted together.

In this spindle motor, since the inner peripheral surface of the sleeve is ground after the hub and the sleeve are fitted together, the inner peripheral surface of the sleeve is deformed due to stress due to the close fitting of the hub and the sleeve. In the case of occurrence of, the deformation can be corrected by polishing to obtain a highly accurate inner peripheral surface. The close fitting here means a case where the stress acting between the members due to fastening such as shrink fitting, press fitting, and adhesion is in a contact relationship such that the members are deformed.

Thus, the outer peripheral surface corresponding to the bearing surface of the inner peripheral surface of the sleeve can be tightly fitted and fastened to the hub, and there is no problem of restriction of axial dimension and bearing performance as in the prior art. In addition, since the inner peripheral surface of the portion of the hub where the mounting portion is provided secures a gap with the outer peripheral surface of the sleeve, when mounting the mounted object on the outer peripheral surface of the hub, The load does not act easily. As a result, the accuracy of the inner peripheral surface of the sleeve can be increased in the gas radial dynamic pressure bearing portion. As a result, the desired bearing capacity can be exhibited and the rotating member can be stably held.

A method of manufacturing a spindle motor according to a second aspect is applied to a spindle motor having the following structure. The spindle motor includes a stationary member, a rotating member,
It has a stator and a rotor magnet. The stationary member has a shaft. The rotating member has a sleeve having a through hole through which the shaft is inserted through a minute gap,
The outer peripheral surface of the sleeve is closely fitted to the inner peripheral surface, and the outer peripheral surface has a tubular hub on which a mounted object is mounted. The stator is fixed to the stationary member. The rotor magnet is fixed to the hub so as to face the stator and cooperates with the stator to generate a rotating magnetic field. A minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and the gas held in the minute gap constitute a radial dynamic pressure bearing portion that rotatably supports the rotating member with respect to the stationary member. . On the outer peripheral surface of the hub, a mounting portion that supports the mounted object in the axial direction is formed. The inner peripheral surface of the portion of the hub where the mounting portion is provided secures a gap between the inner peripheral surface and the outer peripheral surface of the sleeve. This gap can be formed by removing at least one of the hub inner peripheral surface and the sleeve outer peripheral surface.

This manufacturing method includes the following steps. ◎ Process of fitting hub and sleeve ◎ Process of grinding inner peripheral surface of sleeve after fitting hub and sleeve ◎ Process of assembling rotating member and stationary member after the grinding process Since the inner peripheral surface of the sleeve is ground after fitting the sleeve and the sleeve, if deformation occurs due to stress acting on the inner peripheral surface of the sleeve due to close fitting of the hub and the sleeve, the deformation is corrected by polishing. As a result, it is possible to obtain a highly accurate inner peripheral surface.
Thus, the outer peripheral surface corresponding to the bearing surface of the inner peripheral surface of the sleeve can be closely fitted and fastened to the hub, and there is no problem of restriction of axial dimension and bearing performance as in the prior art. In addition, the inner peripheral surface of the portion where the mounting portion is provided in the hub is
Since a gap is secured between the sleeve and the outer peripheral surface, it is difficult for a load to act on the sleeve from the mounting portion when the mounted object is mounted on the outer peripheral surface of the hub. As a result, the accuracy of the inner peripheral surface of the sleeve can be increased in the gas radial dynamic pressure bearing portion. As a result, the desired bearing capacity can be exhibited and the rotating member can be stably held.

The method of manufacturing a spindle motor according to claim 3 is applied to a spindle motor having the following structure. The spindle motor includes a stationary member, a rotating member,
It has a stator coil and a rotor magnet.
The stationary member has a shaft. The rotating member has a cylindrical shape in which a sleeve having a through hole through which a shaft is inserted through a minute gap is formed, and an outer peripheral surface of the sleeve is closely fitted to an inner peripheral surface of the sleeve and a mounting object is mounted on the outer peripheral surface thereof. And a hub. The stator is fixed to the stationary member. The rotor magnet is fixed to the hub so as to face the stator and cooperates with the stator to generate a rotating magnetic field. A minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and the gas held in the minute gap constitute a radial dynamic pressure bearing portion that rotatably supports the rotating member with respect to the stationary member. .

This manufacturing method includes the following steps. ◎ Process of fitting the hub and sleeve ◎ Process of mounting the dummy mounting material on the outer peripheral surface of the hub ◎ Process of polishing the inner peripheral surface of the sleeve with the dummy mounting material mounted on the hub ◎ Dummy after polishing processing Step of removing the mounted object from the hub ◎ Step of assembling the rotating member and the stationary member after polishing processing In this spindle motor manufacturing method, the inner circumference of the rotating sleeve is fitted with the hub closely attached to the rotating sleeve. Since the surface is ground, the accuracy of the inner peripheral surface due to the fastening of the hub and the rotating sleeve can be improved. Conventionally, since the inner peripheral surface of the sleeve is ground before being fitted with the hub, the deformation due to the fitting with the hub cannot be corrected.

Further, since the inner peripheral surface of the rotary side sleeve is ground while the dummy mounted object is mounted on the hub,
The inner peripheral surface of the sleeve when the original mounted object is mounted reproduces the state where it was polished when the dummy mounted object was mounted, and as a result, the inner peripheral surface of the rotating side sleeve is deformed due to the load from the mounted object. It can be modified to improve accuracy. As a result, the accuracy of the inner peripheral surface of the rotating sleeve can be increased, and as a result, the desired bearing capacity can be exhibited and the rotating member can be stably held.

According to a fourth aspect of the present invention, in the spindle motor manufacturing method according to the third aspect, in the step of fitting the hub and the sleeve, the hub is brought into close contact with the entire outer peripheral surface of the sleeve in the axial direction. In the method of manufacturing the spindle motor, in addition to the effect of the manufacturing method according to the third aspect, the dimension of the inner peripheral surface forming the bearing portion of the sleeve is not further restricted. Therefore, the shaft rigidity of the radial dynamic pressure bearing portion is improved.

A spindle motor according to a fifth aspect of the present invention comprises a stationary member, a rotating member, a stator coil, and a rotor magnet. The stationary member has a shaft.
The rotating member has a cylindrical shape in which a sleeve having a through hole through which a shaft is inserted through a minute gap is formed, and an outer peripheral surface of the sleeve is closely fitted to an inner peripheral surface of the sleeve and a mounting object is mounted on the outer peripheral surface thereof. And a hub. The stator is fixed to the stationary member. The rotor magnet is fixed to the hub so as to face the stator and cooperates with the stator to generate a rotating magnetic field. A minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and the gas held in the minute gap constitute a radial dynamic pressure bearing portion that rotatably supports the rotating member with respect to the stationary member. . The hub is in close contact with the entire outer peripheral surface of the sleeve in the axial direction, and the mounted object is also mounted on the outer peripheral surface of the hub corresponding to the sleeve.
The fitted state of the hub and the sleeve is almost uniform in the axial direction, and the mounting of the mounted object on the hub is also almost uniform in the axial direction, and as a result, the stress acts almost uniformly on the inner peripheral surface of the sleeve. There is.

In this spindle motor, since the stress acts almost uniformly on the inner peripheral surface of the sleeve, the inner peripheral surface is less likely to be deformed than in the case where it is partially applied, and high accuracy can be obtained. it can. As a result, the desired bearing capacity can be exhibited and the rotating member can be stably held. According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the hub has a substantially uniform wall thickness in a contact section with the sleeve, and the mounted object is mounted substantially uniformly in the contact section.

In this spindle motor, since stress is uniformly applied to the inner peripheral surface of the sleeve, the inner peripheral surface is unlikely to be deformed and high accuracy can be obtained. As a result, the desired bearing capacity can be exhibited and the rotating member can be stably held. A spindle motor according to a seventh aspect includes a stationary member, a rotating member, a stator coil, and a rotor magnet. The stationary member has a shaft. The rotating member includes a sleeve having a through hole through which the shaft is inserted with a slight gap, and a cylindrical hub in which the outer peripheral surface of the sleeve is fitted to the inner peripheral surface with a clearance and the load is mounted on the outer peripheral surface. Have. The clearance fit here means that the stress acting between the members is in a contact relationship such that the members are not substantially deformed. The stator is fixed to the stationary member. The rotor magnet is fixed to the hub so as to face the stator and cooperates with the stator to generate a rotating magnetic field. A minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and the gas held in the minute gap constitute a radial dynamic pressure bearing portion that rotatably supports the rotating member with respect to the stationary member. . The hub is provided with a stopper that prevents the sleeve from moving relative to the hub.

In this spindle motor, the hub and the sleeve are fitted in a gap, and a stopper is provided at one end of the hub to prevent the sleeve from moving with respect to the hub. The stress does not act on the inner peripheral surface of the sleeve, and the stress from the mounted object is absorbed in the gap, so that the inner peripheral surface is unlikely to be deformed and high accuracy can be obtained. As a result, the desired bearing capacity can be exhibited and the rotating member can be stably held.

The method of manufacturing a spindle motor according to claim 8 is applied to a spindle motor having the following structure. The spindle motor includes a stationary member, a rotating member,
It has a stator coil and a rotor magnet.
The stationary member has a shaft. The rotating member includes a sleeve having a through hole through which the shaft is inserted with a slight gap, and a cylindrical hub in which the outer peripheral surface of the sleeve is fitted to the inner peripheral surface with a clearance and the load is mounted on the outer peripheral surface. Have. The stator is fixed to the stationary member. The rotor magnet is fixed to the hub so as to face the stator and cooperates with the stator to generate a rotating magnetic field. A minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and the gas held in the minute gap constitute a radial dynamic pressure bearing portion that rotatably supports the rotating member with respect to the stationary member. .

The method of manufacturing this spindle motor is as follows.
The following steps are provided. ◎ Process of polishing the inner peripheral surface of the sleeve ◎ Process of fitting the hub and sleeve in a gap ◎ Process of providing the hub with a stopper to prevent the sleeve from moving with respect to the hub ◎ Process of assembling the rotating member and the stationary member This spindle In the motor manufacturing method, after the hub and the sleeve are fitted together with a gap, a stopper is provided at one end of the hub to prevent the sleeve from moving with respect to the hub. No stress acts, and the stress from the mounted object is absorbed in the gap, so that the inner peripheral surface is unlikely to be deformed. As a result, the desired bearing capacity can be exhibited and the rotating member can be stably held.

The above-mentioned mounted object may be various things depending on the application of the spindle motor, for example, a recording disk for a recording disk drive device, and a polygon mirror drive of a laser beam printer. A polygon mirror is used for the device, and a color wheel is used for a color wheel driving device mounted on the projector.

According to a ninth aspect of the present invention, there is provided a recording disk drive device, which comprises a housing and a spindle motor according to any one of the first to fifth aspects fixed to the inside of the housing, or any one of the second to third aspects. A spindle motor manufactured by the manufacturing method described in 1 above, a disk-shaped recording medium fixed to a rotating member capable of recording information, and an information access unit for writing or reading information at a required position of the recording medium. ing.

In this recording disk drive, since the spindle motor is used, the rotating member is stably held, and therefore the recording density of the recording medium can be increased and the capacity can be increased.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION 1. First Embodiment (1) Overall Motor Structure FIG. 1 shows a spindle motor 1 as an embodiment of the present invention.
3 is a vertical cross-sectional view schematically showing the schematic configuration of FIG. The spindle motor 1 is a spindle motor for driving a recording disk, and constitutes a part of a recording disk driving device such as a hard disk.

OO shown in FIG. 1 is the axis of rotation of the spindle motor 1. Further, in the description of the present embodiment, the top and bottom of FIG. 1 are referred to as “up and down in the axial direction” for convenience, but the direction in the actual mounting state of the spindle motor 1 is not limited. In FIG. 1, the spindle motor 1 mainly includes a stationary member 2, a rotating member 3, and a rotating member 3.
Bearing means 4 for rotatably supporting the stationary member 2 on the stationary member 2.

The stationary member 2 includes a shaft 8 and a shaft 8
The base plate 9 fixed to the lower end of the shaft 8, the fixed sleeve 10 fitted to the outer peripheral surface of the shaft 8, and the upper thrust plate 1 arranged at the upper end of the fixed sleeve 10.
1 and a lower thrust plate 12 arranged at the lower end of the fixed sleeve 10. Rotating member 3
Is composed of a hub 13 that fixedly holds a recording disk 83 (described later), and a rotating sleeve 14 that is fitted to the inner peripheral surface of the hub 13.

The bearing means 4 is a dynamic pressure bearing, and more specifically, it is a gas dynamic pressure bearing using gas as a lubricating fluid for both the radial bearing portion and the thrust bearing portion. The spindle motor 1 further includes a stator 6 including a stator core and a coil fixed to the stationary member 2, and a rotating member 3.
The rotor magnet 7 fixed to the rotary member 3 is provided, and both members constitute a magnetic circuit unit for applying a rotational force to the rotating member 3.

(2) The stationary member shaft 8 is a cylindrical member made of stainless steel and extending in the axial direction. A male screw 8a is provided on the lower end of the shaft 8.
Is formed, and the upper end of the shaft 8 is screwed into a female screw 9b formed in the central portion 9a of the base plate 9 and is screwed into a device housing (not shown) in which the spindle motor is mounted. The base plate 9 is a generally disk-shaped member made of an aluminum alloy, the central portion 9a is formed in a cylindrical shape projecting upward in the axial direction from the disk-shaped main body, and the outer peripheral side is the inner periphery of the outer peripheral side cylindrical portion 9c. The stator 6 is mounted on the surface. The central portion 9a has the same diameter as the shaft 8 and integrally forms a cylindrical portion of the stationary member 2. The base plate 9 is also mounted on the device housing (not shown) like the shaft 8. In addition,
A magnetic shield plate S is mounted above the stator 6 to prevent magnetic leakage to the recording disk 83.

The fixed sleeve 10 is a tubular member made of stainless steel and having a uniform thickness, and is fitted to the outer peripheral surface of the shaft 8. The fitting method may be any of shrink fitting, press fitting, adhesion and the like. The outer peripheral surface 10a of the fixed-side sleeve 10 is a shaft outer peripheral surface and constitutes a bearing surface of a radial bearing portion described later. The upper thrust plate 11 is a member which is made of stainless steel and constitutes a bearing surface of a thrust bearing portion which will be described later, and is an annular and disk-shaped member which is fitted to the outer peripheral surface of the shaft 8. The shaft 8 is formed with an annular stopper portion 8b that projects radially outward from the outer peripheral surface. The stopper portion 8b is in contact with the axially upper side surface of the inner peripheral portion of the upper thrust plate 11,
As a result, the upper thrust plate 11 fitted in the clearance is sandwiched and fixed between the stopper portion 8b of the shaft 8 and the upper end surface of the stationary sleeve 10. The outer diameter of the upper thrust plate 11 is larger than the outer diameter of the fixed sleeve 10,
That is, the outer peripheral portion of the upper thrust plate 11 further projects radially outward from the outer peripheral surface 10 a of the fixed sleeve 10.

The lower thrust plate 12 is a member made of stainless steel for constituting a bearing surface of a thrust bearing portion, which will be described later, and is an annular and disk-shaped plate fitted to the central portion 9a of the base plate 9. The lower thrust plate 12 is in contact with the axially upper side surface of the inner peripheral side portion of the base plate 9. In this way, the lower thrust plate 12 fitted in the gap is sandwiched and fixed between the base plate 9 and the lower end surface of the fixed sleeve 10. The outer diameter of the lower thrust plate 12 is larger than the outer diameter of the fixed sleeve 10, that is, the lower thrust plate 1
The outer peripheral portion 2 further protrudes radially outward from the outer peripheral surface 10 a of the stationary sleeve 10.

The stationary sleeve 1 which constitutes the bearing portion
0, the upper thrust plate 11 and the lower thrust plate 12 have a large hardness difference from a rotating sleeve described later and may be damaged or worn as they are.
Diamond-like carbon coating is applied to the outer peripheral surface of 0, the lower surface of the upper thrust plate 11, and the upper surface of the lower thrust plate 12. (3) Rotating member The rotating member 3 is composed of a plurality of tubular members fixed to each other, and is mainly composed of the hub 13 and the rotating sleeve 14.

The hub 13 is a member for mounting a plurality of recording disks 83, and is a member made of cylindrical stainless steel extending in the axial direction. The hub 13 includes an upper end portion 13a and a tubular portion 13b. Hub 1
The upper end portion 13a of 3 has a relatively large radial thickness and is a portion to which a disc clamp described later is attached,
The upper thrust plate 11 is arranged on the axially upper side with a slight gap. The cylindrical portion 13b is the upper end portion 13
It is a thin-walled cylindrical portion that extends axially downward from the outer peripheral side of a.

A recording disk mounting outer peripheral surface 13c, a flange portion 13d, and a rotor holding outer peripheral surface 13e are formed on the outer peripheral surface of the hub 13 from the upper side to the lower side in the axial direction. The flange portion 13d is an annular protrusion that protrudes outward in the radial direction on the outer peripheral surface of the hub 13, and is a mounting portion for supporting the axial load from the recording disk 83 and the spacer 91. The rotor magnet 7 is attached to the rotor holding outer peripheral surface 13e.

The recording disk 83, as shown in FIG.
It is attached to the spindle motor 1 by a disc clamp 92 and a clamp screw 93. The recording disk 83 is four members arranged side by side in the axial direction, and the inner peripheral surface thereof is fitted to the outer peripheral surface 13 c of the hub 13.
Further, the recording disk 83 at the bottom is the flange portion 13 of the hub 13.
Spacers 91 are arranged between the inner peripheral ends of the respective recording disks 83, respectively, in contact with the axially upper end surface of d. The disc clamp 92 is a disc-shaped leaf spring member made of, for example, stainless steel, and has a curved shape in which a central portion thereof projects upward in the axial direction in a free state. The disc clamp 92 is arranged close to the axially upper side of the hub 13. Further, the outermost edge of the disc clamp 92 extends downward in the axial direction, and the uppermost recording disc 8 is formed.
A protruding portion 92a is formed so as to abut the side surface of No. 3. The clamp 92 has an inner peripheral portion fixed to the upper end surface of the upper end portion 13a of the hub 13 by a plurality of clamp screws 93,
Therefore, the inner peripheral portion is urged downward in the axial direction with respect to the upper end portion 13a of the hub 13 to bend so as to have a flat plate shape, and the bending reaction force is applied to the recording disk 83 from the protruding portion 92a. In this way, the recording disk 83 is fixedly mounted on the hub 13 by being sandwiched between the clamp 92 and the flange portion 13d.

On the inner peripheral surface of the hub 13, a contact surface 13f and
Gap securing surface 13g having a diameter slightly larger than the contact surface 13f
And are arranged side by side in this order from the upper side to the lower side in the axial direction. The contact surface 13f is located axially above the flange 13d. That is, the gap securing surface 13g is the collar 1
3d starts from above and extends to the lower end of the tubular portion 1
It is formed in a range of approximately two-thirds in the axial direction of 3b.

The rotating sleeve 14 has an outer peripheral surface 14a.
Is fastened to the contact surface 13f by shrink fitting, and both members are closely fitted to each other. The clearance securing surface 13g secures a slight clearance in the radial direction with the axially lower side portion of the outer peripheral surface 14a of the rotating sleeve 14. Since the rotation-side sleeve 14 has substantially the same axial dimension of the cylindrical portion 13b, the outer peripheral surface of the rotation-side sleeve 14 is in close contact with the hub 13 in a range of approximately one-third in the axial direction, and the remaining approximately two-thirds of the remaining area. The ranges are not in close contact. As is clear from the above description, the inner peripheral surface of the cylindrical portion 13b of the hub 13 near the flange portion 13d has a gap securing surface 13g.
Thus, a gap is secured between the rotating sleeve 14 and the outer peripheral surface 14a.

The rotary sleeve 14 is a cylindrical member made of a ceramic material and having a uniform thickness.
It is arranged on the outer peripheral side of 0. The inner peripheral surface 14b of the rotating sleeve 14 and the outer peripheral surface 10a of the stationary sleeve 10 form a minute gap in the radial direction. The upper end surface 14c of the rotation-side sleeve 14 faces the lower thrust surface 11a of the outer peripheral portion of the upper thrust plate 11 with a minute gap. Lower end surface 14d of the rotating sleeve 14
Are opposed to the upper thrust surface 12a of the outer peripheral portion of the lower thrust plate 12 with a minute gap.

In the hub 13, the mounting outer peripheral surface 13c on which the recording disk 83 and the spacer 91 are mounted and the flange portion 13d must be accurately positioned, and stainless steel having magnetism is used in terms of cutting. Has been done. Further, the rotating sleeve 14 is made of ceramics because the inner peripheral surface 14b forming a part of the radial bearing portion 35 needs to have slidability and wear resistance. It should be noted that by selecting materials having a small difference in thermal expansion coefficient between the hub 13 and the rotating sleeve 14, thermal strain due to the difference in thermal expansion coefficient is less likely to occur, and the inner peripheral surface of the rotating sleeve 14 is prevented. 14
The accuracy of b can be improved.

(4) Bearing Means The bearing means 4 is a dynamic pressure bearing that rotatably supports the rotating member 3 with respect to the stationary member 2 and uses gas as a lubricating fluid, and is a radial bearing portion 35. And thrust bearing portions 41 and 42. Radial bearing part 3
Reference numeral 5 is composed of an outer peripheral surface 10a of the fixed sleeve 10, an inner peripheral surface 14b of the rotary sleeve 14, and air existing in a minute gap therebetween. In this case, the dynamic pressure generating groove may be formed on one of the outer peripheral surface 10a and the inner peripheral surface 14b, or may not be formed on either of them. Also,
The dynamic pressure generating groove may have any shape such as a herringbone groove, a spiral groove, or a step groove. Further, the radial bearing portion may be composed of two radial bearing portions arranged in the axial direction.

The thrust bearing portions 41, 42 are composed of a first thrust bearing portion 41 on the axially upper side and a second thrust bearing portion 42 on the axially lower side. The first thrust bearing portion 41 includes a lower thrust surface 11 a of the upper thrust plate 11 and an upper end surface 14 c of the rotary sleeve 14.
It is composed of the gas existing in the minute gap. The second thrust bearing portion 42 is composed of the upper thrust surface 12a of the lower thrust plate 12, the lower end surface 14d of the rotary sleeve 14, and the gas existing in the minute gap. In this case, in each of the thrust bearing portions 41, 42, the dynamic pressure generating groove may be formed in one of the thrust surfaces facing each other, or may not be formed in any of them. Further, the dynamic pressure generating groove may have any shape such as a herringbone groove, a spiral groove, or a step groove.

(5) Rotational operation When the coil of the stator 6 is energized, the rotating member 3 together with the recording disk 83 is caused to rotate by the magnetic circuit portion of the stator 6 and the rotor magnet 7, and the radial bearing portion 35 and the thrust bearing portions 41, 42. It rotates with respect to the stationary member 2 while being supported via. At this time, in the radial bearing portion 35, the radial load supporting pressure is generated by the air in the minute gap between the outer peripheral surface 10a of the stationary sleeve 10 and the inner peripheral surface 14b of the rotating sleeve 14. In the thrust bearing portions 41, 42, the thrust plates 11, 1
2 and the upper and lower end surfaces 14c and 1 of the rotary sleeve 14
The thrust load supporting pressure is generated by the gas in the gap with 4d.

Radial bearing portion 35 and thrust bearing portion 4
Since 1 and 42 use air dynamic pressure, the structure is simplified without the need for a seal structure for preventing leakage of lubricating fluid unlike oil dynamic pressure, and the air is not exhausted, so lack of lubricating fluid is eliminated. This is advantageous in terms of life, and since the viscosity variation of air is small in a wide temperature range, the radial rigidity becomes constant, and the characteristics can be easily guaranteed even at high temperatures.

(6) Manufacturing Method Next, a method of manufacturing the spindle motor 1 will be described. First, as shown in FIG. 2, the hub 13 of the rotating member 3 is
And the rotary sleeve 14 are fitted together. The fitting method is a method in which the fastening portion is shrink-fitted, and press-fitting, adhesive bonding, and the like are brought into close contact with each other.
From the above, a constant load acts on the rotating sleeve 14, so that the fixing strength is obtained, but the inner peripheral surface 14b of the rotating sleeve 14 is deformed unevenly, and the inner diameter of the fastening portion side becomes a tapered shape. . At the time of this fitting, the upper thrust plate 11 which is a part of the stationary member 2 is temporarily fitted between the two members.

Next, the inner peripheral surface 14b of the rotating sleeve 14
Is subjected to finishing (polishing) to correct the deformation caused by the fitting. As a result, the accuracy of the inner peripheral surface 14b of the rotating sleeve 14 can be increased in the fitted state of the hub 13 and the rotating sleeve 14. After this, the rotor magnet 7 is attached to the hub 1.
Fix to 3. Further, the base plate 9 including the stator 6 and the magnetic shield plate S and the lower thrust plate 1
2 and the stationary side sleeve 10 are assembled to each other to form an integrated structure, and as shown in FIG. 3, they are assembled to the rotating member 3 including the hub 13 and the rotating side sleeve 14 described above.

Finally, the shaft 8 is fixed to the fixed sleeve 10.
The male screw 8a at the tip is screwed into the female screw 9b of the central portion 9a of the base plate 9 while being fitted to the inner peripheral side of the base plate by a clearance fit, and the tightening force of the shaft 8 causes the stopper portion 8b to move to the upper thrust plate 11 and the fixed sleeve 10. The lower thrust plate 12 is collectively pressed against the base plate 9 to complete the assembly of the stationary member 2. As a result, the basic configuration of the spindle motor 1 is completed.

Subsequently, the recording disk 83 is mounted on the hub 13. Specifically, the plurality of recording disks 83 and the spacer 91 are fitted to the outer peripheral surface 13c of the hub 13, and then the clamp 92 is fixed by the clamp screw 93. As a result, the flexure reaction force of the clamp 92 causes the recording disk 8 to move.
3 is urged against the flange portion 13d of the hub 13. In addition,
The recording disk 83 can be mounted after the spindle motor 1 is attached to the apparatus housing.

The load acting from the recording disk 83 to the inner side in the radial direction with respect to the hub 13 is not uniform in the axial direction due to the wall thickness of the hub 13 and the mounting state of the recording disk 83 and the like, and the axial direction of the cylindrical portion 13b. Collar part 13 from the top
The part of d becomes large. However, in this embodiment, since a gap is secured between the inner peripheral surface of the tubular portion 13b and the outer peripheral surface of the rotary sleeve 14 by the gap securing surface 13g, the vicinity of the flange portion 13d of the tubular portion 13b is It may be deformed to the inner peripheral side, but no load is applied to the rotary sleeve 14. As a result, it is difficult for stress to act on the inner peripheral surface 14b of the rotating-side sleeve 14 due to the load of the mounted object, and deformation of the inner peripheral surface 14b does not occur easily. The tubular portion 1
Even if the 3b is deformed as described above, the amount of deformation is very small, which does not impair the rotational accuracy and hinder the information writing and reading operations on the recording disk 83 mounted on the mounting portion 13d.

(7) Effects The following is a summary of the effects of the present invention described above. When assembling the rotary member 3, the hub 13 and the rotary sleeve 14 are fitted to each other, and then the inner peripheral surface 1 of the rotary sleeve 14 is fitted.
Since 4b is polished, the accuracy of the inner peripheral surface 14b can be improved even if deformation occurs after fitting. Conventionally, since the inner peripheral surface of the sleeve was ground before being fitted with the hub, it was not possible to correct the deformation due to the fitting with the hub. In addition, by predicting the amount of deformation after fitting before fitting, and setting the inner diameter and axial length of the contact surface 13f of the hub 13 and the like, the inner peripheral surface 14b of the rotating sleeve 14 after fitting is desired. There is a method to make it the shape of
In fact, assembling such a member complicates the part processing and significantly impairs mass productivity. As is apparent from comparison with such a method, the present invention can achieve a desired configuration by a very simple method.

Further, by adopting the manufacturing method as described above, there is an advantage that a fitting method such as shrink fitting, press fitting, and adhesion which is relatively simple and has high fastening strength can be freely adopted. A clearance securing surface 1 is provided below the inner peripheral surface of the tubular portion 13b of the hub 13.
Since 3 g is provided, the load of the mounted object such as the recording disk 83 acts evenly on the rotating sleeve 14, and the inner peripheral surface 14 b is unlikely to be deformed.

As a result, the accuracy of the inner peripheral surface of the gas radial bearing portion 35 can be improved. As a result, a desired bearing capacity can be exhibited, and the rotating member 3 and thus the recording disk 83 can be stably held. (8) Configuration of Hard Disk Device An embodiment of the recording disk driving spindle motor 1 according to the present invention has been described above, but a hard disk device as a recording disk driving device including the spindle motor 1 according to the present invention will be described as an example. To do.

FIG. 14 shows a general hard disk device 8
The internal structure of 0 is shown as a schematic diagram. The inside of the housing 81 forms a clean space in which dust and the like are extremely small, and the spindle motor 1 having the disk-shaped recording disk 83 for storing information is installed therein. . In addition, a magnetic head moving mechanism 87 for reading / writing information from / into the recording disk 83 is arranged inside the housing 81. The magnetic head moving mechanism 87 reads / writes information on / from the recording disk, The supporting arm 85 and the actuator section 8 for moving the head and the arm to desired positions on the disk.
It is composed of four.

In such a hard disk device 80,
By rotating the spindle motor 1, the recording disk 83 is rotationally driven in a predetermined direction. The actuator section 84 pivots the arm 85, and the head 86 mounted on them moves in the substantially radial direction of the corresponding recording disk 83, and as a result, the recording information to be recorded is magnetically recorded on the recording disk 83 by the action of the head 86. The recording information recorded on the recording disk or recorded on the recording disk 83 is read by the head 86.

In this hard disk device 80, since the spindle motor 1 is used, the rotary member 3 is stably held, and therefore the recording density of the recording disk 83 can be increased and the capacity can be increased. 2. Second Embodiment (1) Configuration A spindle motor 1 according to a second embodiment of the present invention will be described with reference to FIGS. 4 to 6. In the figure, the same numbers are assigned to the same structures as in the first embodiment.

The second embodiment has the same basic structure as that of the first embodiment, and in the following description, mainly different points will be described. In this embodiment, the tubular portion 13 of the hub 13
Similarly to the first embodiment, b covers the outer peripheral side of the rotary sleeve 14 over the entire surface. However, unlike the first embodiment, the inner peripheral surface 13j of the tubular portion 13b is in close contact with the entire outer peripheral surface 14a of the rotating sleeve 14 in the axial direction.

(2) Manufacturing Method A method of manufacturing the spindle motor 1 will be described.
First, as shown in FIG. 5, the hub 13 of the rotary member 3 and the rotary sleeve 14 are fitted together. As a fitting method,
This is a method in which the fastening portion is shrink-fitted, press-fitted, adhered and the like to be brought into close contact with each other. However, in any case, a fixed load acts on the rotary sleeve 14 from the hub 13, so that the fixing strength is obtained. Here, it is assumed that the inner peripheral surface 14b of the rotation-side sleeve 14 is deformed in such a fitting state that it is deformed even a little. At the time of this fitting, the upper thrust plate 11 which is a part of the stationary member 2 is temporarily fitted between the two members.

Next, as shown in FIG. 6, the dummy mount 6
1 is mounted on the hub 13. The dummy mount 61 is preferably a ring having the same total length as the total length of the recording disc 83 and the spacer 91 which are the actual mounts.
5 and the clamp screw 66 are the same as the actual ones, and the tightening torque of the clamp screw 66 is also the same as the actual one. The load acting from the dummy mount 61 to the inside of the hub 13 in the radial direction is not uniform in the axial direction, and the tubular portion 13
It becomes larger at the flange portion 13d than at the axially upper portion of b. Therefore, stress acts on the inner peripheral surface 14b of the rotary sleeve 14 due to the load of the mounted object, and the inner peripheral surface 14b is deformed into a tapered shape in which the inner diameter of the axially lower portion is reduced.

Next, the inner peripheral surface 14b of the rotating side sleeve 14
Is finished (polished) to correct the fitting with the hub 13 and the deformation due to the dummy mount 61. As a result, the accuracy of the inner peripheral surface 14b of the rotary sleeve 14 can be increased in the state where the dummy mount 61 is mounted. Then, the dummy mount 61 is removed from the hub 13. Dummy loading 6
When the load from No. 1 is released, the hub 13 and the rotation-side sleeve 14 have their axially lower portions expanded in diameter, and the accuracy again decreases. After that, the rotor magnet 7 is fixed to the hub 13.

Further, as described in the first embodiment, the base plate 9 provided with the stator 7 and the magnetic shield plate S, the lower thrust plate 12 and the fixed sleeve 10 are assembled together to form an integral structure. Is assembled to the rotating member 3 including the hub 13 and the rotating sleeve 14 described above. Finally, while the shaft 8 is fitted to the inner peripheral side of the fixed sleeve 10 by a clearance fit, the male screw 8a at the tip is attached to the female screw 9 of the central portion 9a of the base plate 9.
It is screwed to b and the stopper 8 is tightened by the tightening force of the shaft 8.
b is the upper thrust plate 11, the fixed sleeve 10,
The lower thrust plate 12 is collectively attached to the base plate 9
And the assembly of the stationary member 2 is completed. As a result, the basic configuration of the spindle motor 1 is completed.

Subsequently, the recording disk 83 is mounted on the hub 13. Specifically, the plurality of recording disks 83 and the spacer 91 are fitted to the outer peripheral surface 13c of the hub 13, and then the clamp 92 is fixed by the clamp screw 93. As a result, the flexure reaction force of the clamp 92 causes the recording disk 8 to move.
3 is urged against the flange portion 13d of the hub 13. In addition,
The recording disk 83 can be mounted after the spindle motor 1 is attached to the apparatus housing.

In this way, the recording disk 83, etc.
When loaded on the disk, a load acts on the hub 13 from the recording disk 83. In particular, a large load is applied near the flange portion 13d of the hub 13, and the inner peripheral surface 14b of the rotating sleeve 14 is deformed. As a result, the inner peripheral surface 14b has the dummy mount 61
The state is restored to the same as when it was mounted and further polished, and the highly accurate state at that time is reproduced. (3) Effects The following is a summary of the effects of the present invention described above.

Since the inner peripheral surface 14b of the rotating sleeve 14 is ground while the hub 13 is fitted in the rotating sleeve 14, even if the hub 13 and the rotating sleeve 14 are deformed after fitting. The accuracy of the inner peripheral surface 14b due to the fastening of 14 can be improved. Furthermore, since the inner peripheral surface 14b of the rotary sleeve 14 is ground while the dummy mount 61 is mounted on the hub 13, the rotary sleeve 14 due to the load from the mount is used.
It is possible to reduce the deformation of the inner peripheral surface 14b and improve the accuracy.

As a result, the accuracy of the inner peripheral surface of the gas radial bearing portion 35 can be improved, and the rotating member 3 and thus the recording disk 83 can be stably held. Compared with the first embodiment, although the work of mounting and removing the dummy mount is increased, the hub 13 can be entirely adhered to the rotating sleeve 14, so that the bearing rigidity of the radial bearing portion 35 is increased. Becomes higher. Further, since it is not necessary to provide the gap securing surface 13g of the hub 13, the processing of the hub 13 becomes easy.

3. Third Embodiment (1) Configuration A spindle motor 1 according to a third embodiment of the present invention will be described with reference to FIGS. 7 and 8. In the figure, the first
The same numbers are attached to the structures equivalent to those of the embodiment.

The basic structure of the third embodiment is the same as that of the first embodiment, and different points will be mainly described in the following description. In this embodiment, the axial lengths of the stationary sleeve 10 and the rotating sleeve 14 are shorter than those in the above embodiment. Specifically, the central portion 9d of the base plate 9 is raised in the axial direction, and the lower thrust plate 12 is arranged at the same axial position as the flange portion 13d of the hub 13. That is, the lower ends of the stationary sleeve 10 and the rotating sleeve 14 extend only near the flange portion 13d of the hub 13 or before this. The entire outer peripheral surface 14a of the rotating sleeve 14 is in close contact with the inner peripheral surface 13k of the hub 13, and the mounting outer peripheral surface 13c of the hub 13 corresponds in length and position in the axial direction. Hub 13 and rotating sleeve 14
The inner peripheral surface 14 of the rotation-side sleeve 14 is fitted with the fastening portion by shrink fitting, press-fitting, adhering, or the like.
It is fitted to the extent that b is deformed.

The recording disk 83 and the spacer 91 are different from those in the first and second embodiments in that they are shrink-fitted, press-fitted,
The mounting outer peripheral surface 13c of the hub 13 is closely fitted and fixed by a fitting method such as adhesion. That is, unlike the above-described embodiment, neither a clamp nor a bolt is provided, and the hub 13 does not have a thick portion like the upper end portion. Therefore, firstly, the hub 13 has a substantially uniform wall thickness (radial thickness) in the portion corresponding to the fitting surface with the rotating sleeve 14. Secondly, the recording disk 83 and the spacer 91 are
The hub 13 is evenly mounted on the mounting outer peripheral surface 13c.

(2) Manufacturing Method Next, a manufacturing method of the spindle motor 1 will be described. First, the inner peripheral surface 14b of the rotary sleeve 14 is finished (polished). Next, as shown in FIG.
3 and the rotating side sleeve 14 are fitted together. As the fitting method, there are shrink fitting, press fitting, adhesion, etc., but in any case, a fixed load acts on the rotating sleeve 14 from the hub 13 and therefore a fixing strength is obtained. Moreover, by making the wall thickness of the contact portion of the hub 13 with the rotating sleeve 14 substantially uniform, the hub 13 and the rotating sleeve 1 can be made uniform.
The fitted state of No. 4 is almost uniform in the axial direction. Therefore, the degree of deformation of the inner peripheral surface 14b of the rotating sleeve 14 is also uniform in the axial direction.

Next, the base plate 9, the lower thrust plate 12, and the stationary sleeve 10 are assembled together to form an integral structure, which is assembled to the rotating member 3 composed of the hub 13 and the rotating sleeve 14 described above. Finally, the upper thrust plate 11 is attached to both sleeves 10, 14
And the shaft 8 is fitted to the inner peripheral side of the fixed sleeve 10, and the male screw 8a at the tip is screwed into the female screw 9b of the central portion 9a of the base plate 9. As a result,
The basic configuration of the spindle motor 1 is completed.

Then, the recording disk 83 is mounted on the hub 13. Specifically, the plurality of recording disks 83 and the spacer 91 are fitted onto the outer peripheral surface 13c of the hub 13 by shrink fitting, press fitting, bonding, or the like. In other words, the recording disk 83 and the spacer 91 are evenly mounted on the portion of the hub 13 that corresponds to the contact section with the rotating sleeve 14.

Thus, the hub 13 and the rotating sleeve 1 are
The fitting state of No. 4 is almost uniform in the axial direction, and the mounting of the recording disk 83 or the like, which is the mounted object, on the hub 13 is also substantially uniform in the axial direction, and as a result, the rotating sleeve 14, the hub 13, and the mounted object. The stress acting on each other after the recording disk 83 and the spacer 91 are fastened uniformly acts on the inner peripheral surface 14b of the rotating sleeve 14 as a whole. As a result, the inner peripheral surface 14b of the rotation-side sleeve 14 is hardly deformed, and even if it is deformed, it is minute and evenly deformed as a whole. Has almost no effect on the occurrence. Therefore, the accuracy of the inner peripheral surface 14b of the rotating sleeve 14 can be improved. As a result, a desired bearing capacity can be exhibited, and the rotating member 3 and thus the recording disk 83 can be stably held.

Further, in this spindle motor manufacturing method, since the inner peripheral surface 14b of the rotary sleeve 14 before assembly can be ground, there is also an effect that the processing operation is simplified. 4. Fourth Embodiment (1) Configuration A spindle motor 1 according to a fourth embodiment of the present invention will be described with reference to FIGS. 9 to 11. In the figure, the first
The same numbers are attached to the structures equivalent to those of the embodiment.

The fourth embodiment has the same basic structure as that of the first embodiment, and in the following description, mainly different points will be described. In this embodiment, the tubular portion 13 of the hub 13
Similarly to the first embodiment, b covers the outer peripheral side of the rotary sleeve 14 over the entire surface. However, unlike the first embodiment, the inner peripheral surface 13j of the tubular portion 13b is fitted in the entire outer peripheral surface 14a of the rotating sleeve 14 in the axial direction. As a result, no load is applied to the rotating sleeve 14 from the hub 13 due to the fitting.

On the other hand, due to the clearance fitting, the rotary sleeve 1
A stopper 71 is provided on the hub 13 to restrict the movement of the 4 with respect to the hub 13. The stopper 71 is a ring fixed to the inner peripheral surface of the lower end portion 13l (a portion extending further downward in the axial direction than the rotating sleeve 14) of the tubular portion 13b of the hub 13. Stopper 7
1 is shrink fitted to the lower end portion 13l of the tubular portion 13b,
It is fixed by press-fitting, adhesion, etc., and is in contact with the lower end surface 14d of the rotating sleeve 14. As a result, the rotating sleeve 1
4 is sandwiched between the step surface 13h of the hub 13 and the stopper 71, and is fixed so as not to move in the axial direction, the circumferential direction, and the radial direction with respect to the hub 13.

(2) Manufacturing Method Next, a manufacturing method of the spindle motor 1 will be described. First, the inner peripheral surface 14b of the rotary sleeve 14 is finished (polished). Next, as shown in FIG. 10, the hub 13 and the rotation-side sleeve 14 are fitted by a clearance fit.

Next, as shown in FIG. 11, the stopper 7
1 is fixed to the lower end portion 131 of the tubular portion 13b of the hub 13. As a result, the rotation-side sleeve 14 is retained (fixed) from the hub 13. Then, the rotor magnet 7 is fixed. Further, the base plate 9, the lower thrust plate 12, and the stationary sleeve 10 are assembled together to form an integral structure, which is assembled to the rotating member 3 including the hub 13 and the rotating sleeve 14 described above.

Finally, the upper thrust plate 11 is mounted on both sleeves 10 and 14, and the male screw 8a at the tip is fitted while the shaft 8 is fitted to the inner peripheral side of the fixed sleeve 10.
Is screwed into the female screw 9b of the central portion 9a of the base plate 9. As a result, the basic configuration of the spindle motor 1 is completed. Then, the recording disk 83 is mounted on the hub 13. Specifically, the plurality of recording disks 83 and the spacer 91 are fitted to the outer peripheral surface 13c of the hub 13. At this time,
The load from the recording disk 83 acts on the hub 13,
The deformation of the hub 13 is absorbed by the gap between the hub 13 and the rotating sleeve 14, and a large load does not act on the rotating sleeve from the hub 13. Therefore, the accuracy of the inner peripheral surface 14b of the rotating sleeve 14 can be improved. As a result, a desired bearing capacity can be exhibited, and the rotating member 3 and thus the recording disk 83 can be stably held.

Further, in this spindle motor manufacturing method, since the inner peripheral surface 14a of the rotary sleeve 14 before being assembled can be ground, there is also an effect that the working operation is simplified. 5. Fifth Embodiment A spindle motor 1 as a fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment is a structure in which a part of the fourth embodiment is modified, and the other basic structures are the same, and mainly different points will be described in the following description. Therefore, in the figure, the same numbers are assigned to the same structures as those of the fourth embodiment in the previous term.

In this embodiment, the stopper 72 for restricting the movement of the rotating sleeve 14 in the axial direction with respect to the hub 13 is screwed to the lower end portion 13l of the tubular portion 13b and Lower end surface 14d of the sleeve 14
Is in contact with. That is, the screw 13i is formed on the inner peripheral surface of the lower end portion 131 of the tubular portion 13b of the hub 13, and the screw 72a is formed on the outer peripheral surface of the stopper 72. As a result, the rotation-side sleeve 14 is provided with the step surface 1 of the hub 13.
It is sandwiched between 3h and the stopper 72, and is fixed to the hub 13 so as not to move in the axial direction, the circumferential direction, and the radial direction.

6. Sixth Embodiment A spindle motor 1 as a sixth embodiment of the present invention will be described with reference to FIG. The sixth embodiment is a structure in which a part of the fourth embodiment is modified, and the other basic structures are the same, and mainly different points will be described in the following description. Therefore, in the figure, the same numbers are assigned to the same structures as those of the fourth embodiment in the previous term.

In this embodiment, the stopper 73 for restricting the movement of the rotary sleeve 14 in the axial direction with respect to the hub 13 has a lower end portion 13l of the tubular portion 13b of the hub 13 (from the rotary sleeve 14). Further, it is an annular projection formed by crimping the portion extending downward in the axial direction) to the inner peripheral side. The stopper 73 is in contact with the lower end surface 14d of the rotating sleeve 14. As a result, the rotating sleeve 14 is sandwiched between the step surface 13h of the hub 13 and the stopper 73, and is fixed so as not to move in the axial direction, the circumferential direction, and the radial direction with respect to the hub 13.

7. Other Embodiments The present invention is not limited to the above embodiments, and various changes or modifications can be made without departing from the scope of the present invention. The type of thrust bearing portion is not limited to a dynamic pressure bearing that uses gas as a lubricating fluid. That is,
The thrust bearing portion may be a dynamic pressure bearing that uses liquid as a lubricating fluid, a magnetic bearing that supports by magnetic force, a sliding bearing by point contact, a rolling bearing that interposes rolling elements, or the like.

The spindle motor according to the present invention can be adopted not only in the hard disk recording device but also in other recording disk driving devices, polygon mirror driving devices of laser beam printers, color wheel driving devices used in projectors, and the like. .

[0086]

According to the spindle motor of the first aspect and the method of manufacturing the spindle motor of the second aspect, since the inner peripheral surface of the sleeve is ground after the hub and the sleeve are fitted, the hub and the sleeve are fitted together. When a stress is applied to the inner peripheral surface of the sleeve due to the combination and the taper shape or the like is deformed, the deformation can be corrected by polishing to obtain the inner peripheral surface with high accuracy. In addition, since the inner peripheral surface of the portion of the hub where the mounting portion is provided secures a gap with the outer peripheral surface of the sleeve, when mounting the mounted object on the outer peripheral surface of the hub, The load does not act easily.
As a result, the accuracy of the inner peripheral surface of the sleeve can be increased in the gas radial dynamic pressure bearing portion. As a result, the desired bearing capacity can be exhibited and the rotating member can be stably held.

In the method of manufacturing the spindle motor according to the third aspect, the hub is fitted to the rotating sleeve,
In addition, since the inner peripheral surface of the rotating sleeve is polished while the dummy mounted object is mounted on the hub, deformation due to the fastening of the hub and the rotating sleeve and the rotating sleeve due to the load from the mounted object The accuracy can be improved by correcting the deformation of the inner peripheral surface. Conventionally, since the inner peripheral surface of the sleeve is polished before fitting with the hub, it is impossible to correct the deformation due to the fitting with the hub and the deformation due to the load from the mounted object. As a result, the accuracy of the inner peripheral surface of the rotating sleeve can be increased, and as a result, the desired bearing capacity can be exhibited and the rotating member can be stably held.

According to the manufacturing method of the spindle motor of the fourth aspect, in addition to the effect of the manufacturing method of the third aspect,
The dimensions of the inner peripheral surface of the bearing portion of the sleeve are not restricted. Therefore, the shaft rigidity of the radial dynamic pressure bearing portion is improved. In the spindle motor according to claim 5,
The fitted state of the hub and the sleeve is uniform in the axial direction, and the mounting of the mounting object on the hub is also uniform in the axial direction. As a result, the stress is uniformly applied to the inner peripheral surface of the sleeve. Therefore, since the stress is uniformly applied to the inner peripheral surface of the sleeve, uneven deformation is unlikely to occur on the inner peripheral surface, and the sleeve is not deformed into a tapered shape (without reducing the cylindricity) and is high. Accuracy can be obtained. As a result, the desired bearing capacity can be exhibited and the rotating member can be stably held.

According to the sixth aspect of the spindle motor,
In claim 5, since the hub has a substantially uniform wall thickness in the contact section with the sleeve and the mounted object is mounted substantially evenly in the contact section, the inner peripheral surface is less likely to be deformed,
High accuracy can be obtained. As a result, the desired bearing capacity can be exhibited and the rotating member can be stably held.

In the spindle motor according to the seventh aspect and the method for manufacturing the spindle motor according to the eighth aspect, the sleeve is prevented from moving relative to the hub at one end of the hub after the hub and the sleeve are fitted in the gap. Since the stopper is provided, stress does not act on the inner peripheral surface of the sleeve due to the fastening of the hub and the sleeve, so that the inner peripheral surface is less likely to be deformed. As a result, the desired bearing capacity can be exhibited and the rotating member can be stably held.

In the recording disk drive device according to the ninth aspect, since the spindle motor is used, the rotating member is stably held, and therefore the recording density of the recording medium can be increased and the capacity can be increased.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a spindle motor adopting a first embodiment of the present invention.

FIG. 2 is a schematic vertical sectional view for explaining an assembly process of the spindle motor of FIG.

FIG. 3 is a schematic vertical sectional view for explaining an assembly process of the spindle motor shown in FIG. 1;

FIG. 4 is a schematic vertical cross-sectional view of a spindle motor that employs a second embodiment of the present invention.

5 is a schematic vertical sectional view for explaining an assembly process of the spindle motor of FIG.

6 is a schematic vertical cross-sectional view for explaining an assembly process of the spindle motor of FIG.

FIG. 7 is a schematic vertical sectional view of a spindle motor adopting a third embodiment of the present invention.

8 is a schematic vertical sectional view for explaining an assembly process of the spindle motor of FIG.

FIG. 9 is a schematic vertical sectional view of a spindle motor adopting a fourth embodiment of the present invention.

FIG. 10 is a schematic vertical sectional view for explaining an assembly process of the spindle motor shown in FIG.

FIG. 11 is a schematic vertical sectional view for explaining an assembly process of the spindle motor of FIG.

FIG. 12 is a schematic vertical sectional view of a spindle motor to which a fifth embodiment of the invention is applied.

FIG. 13 is a schematic vertical cross-sectional view of a spindle motor that employs a sixth embodiment of the present invention.

FIG. 14 is a schematic configuration diagram of a general hard disk device in which the recording disk drive device of the present invention is adopted.

[Explanation of symbols]

1 Spindle motor 2 stationary members 3 rotating members 4 Bearing means 8 shafts 10 Fixed side sleeve 13 hubs 14 Rotating sleeve 35 radial bearing 41 1st thrust bearing part 42 Second thrust bearing portion

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3J011 BA02 CA02 DA02 KA02 KA03                       SD01                 5D109 BA03 BA14 BA18 BA28 BB03                       BB13 BB18 BB21 BB22                 5H605 BB05 BB10 BB14 CC04 DD03                       DD05 EB03 EB06                 5H607 BB01 BB07 BB14 CC03 DD03                       DD16 FF12 GG01 GG03 GG08                       GG09 GG12 GG14 GG15 GG17                       JJ04 JJ06

Claims (9)

[Claims] 1. A stationary member having a shaft, a sleeve having a through hole through which the shaft is inserted with a minute gap, and an outer peripheral surface of the sleeve which is closely fitted to an inner peripheral surface of the outer peripheral surface. A rotating member having a tubular hub on which a load is mounted, a stator fixed to the stationary member, fixed to the hub so as to face the stator, and a rotating magnetic field in cooperation with the stator. A rotor magnet for generating the rotating member with respect to the stationary member by a minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and the gas held in the minute gap. A radial dynamic pressure bearing portion that rotatably supports is configured, a mounting portion that supports the mounted object in the axial direction is formed on the outer peripheral surface of the hub, and the mounting portion is provided in the hub. The inner peripheral surface of the portion secures a gap between the inner peripheral surface of the sleeve and the outer peripheral surface of the sleeve, and the inner peripheral surface of the sleeve is polished after the sleeve and the hub are fitted to each other. Spindle motor. 2. A stationary member having a shaft, a sleeve having a through hole through which the shaft is inserted with a minute gap, and an outer peripheral surface of the sleeve which is fitted in close contact with an inner peripheral surface of the sleeve. A rotating member having a tubular hub on which a load is mounted, a stator fixed to the stationary member, fixed to the hub so as to face the stator, and a rotating magnetic field in cooperation with the stator. A rotor magnet for generating the rotating member with respect to the stationary member by a minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and the gas held in the minute gap. A radial dynamic pressure bearing portion that rotatably supports is configured, a mounting portion that supports the mounted object in the axial direction is formed on the outer peripheral surface of the hub, and the mounting portion is provided in the hub. A method of manufacturing a spindle motor, wherein a gap is secured between the inner peripheral surface of the portion and the outer peripheral surface of the sleeve, the step of fitting the hub and the sleeve, and the hub and the sleeve. A method of manufacturing a spindle motor, comprising: a step of polishing the inner peripheral surface of the sleeve after the fitting, and a step of assembling the rotating member and the stationary member after the polishing. 3. A stationary member having a shaft, a sleeve in which a through hole is formed through which the shaft is inserted with a minute gap formed, and an outer peripheral surface of the sleeve is closely fitted to an inner peripheral surface of the outer peripheral surface. A rotating member having a tubular hub on which a load is mounted, a stator fixed to the stationary member, fixed to the hub so as to face the stator, and a rotating magnetic field in cooperation with the stator. A rotor magnet for generating the rotating member with respect to the stationary member by a minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and the gas held in the minute gap. A method for manufacturing a spindle motor, comprising a radial dynamic pressure bearing portion rotatably supported, comprising: a step of fitting the hub and the sleeve; A step of mounting on the peripheral surface, a step of polishing the inner peripheral surface of the sleeve in a state where the dummy mounting object is mounted on the hub, and a step of removing the dummy mounting object from the hub after the polishing processing. And a step of assembling the rotary member and the stationary member after the polishing process. 4. The method of manufacturing a spindle motor according to claim 3, wherein in the step of fitting the hub and the sleeve, the hub is in close contact with the outer peripheral surface of the sleeve over the entire axial direction. 5. A stationary member having a shaft, a sleeve having a through hole formed therein for allowing the shaft to be inserted through a minute gap, and an outer peripheral surface of the sleeve closely fitted to an inner peripheral surface of the outer peripheral surface. A rotating member having a tubular hub on which a load is mounted, a stator fixed to the stationary member, fixed to the hub so as to face the stator, and a rotating magnetic field in cooperation with the stator. A rotor magnet for generating the rotating member with respect to the stationary member by a minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and the gas held in the minute gap. A radial dynamic pressure bearing portion that rotatably supports is configured, and the hub is in close contact with the entire outer peripheral surface of the sleeve in the axial direction. The hub and the sleeve are mounted in close contact with each other on the peripheral surface, and the fitted state of the hub and the sleeve is substantially uniform in the axial direction. Further, the mounting of the mount on the hub is also substantially uniform in the axial direction. A spindle motor, wherein stress is applied to the inner peripheral surface substantially uniformly. 6. The spindle motor according to claim 5, wherein the hub has a substantially uniform wall thickness in a contact section with the sleeve, and the mount is mounted substantially uniformly over the contact section. 7. A stationary member having a shaft, a sleeve having a through hole through which the shaft is inserted through a minute gap, an outer peripheral surface of the sleeve is fitted to an inner peripheral surface of the sleeve, and an outer peripheral surface is mounted. A rotating member having a cylindrical hub on which is mounted; a stator fixed to the stationary member; and a rotating member fixed to the rotating member so as to face the stator and generating a rotating magnetic field in cooperation with the stator. A rotor magnet for rotating the rotating member with respect to the stationary member by a minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and a gas held in the minute gap. A spindle motor, characterized in that a radial dynamic pressure bearing portion for supporting the sleeve is configured, and the hub is provided with a stopper for suppressing the movement of the sleeve. 8. A stationary member having a shaft, a sleeve having a through hole through which the shaft is inserted through a minute gap, an outer peripheral surface of the sleeve is fitted to an inner peripheral surface of the sleeve, and an outer peripheral surface is mounted. A rotating member having a cylindrical hub on which is mounted; a stator fixed to the stationary member; and a rotating member fixed to the rotating member so as to face the stator and generating a rotating magnetic field in cooperation with the stator. A rotor magnet for rotating the rotating member with respect to the stationary member by a minute gap between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve and a gas held in the minute gap. A method for manufacturing a spindle motor, comprising: a radial dynamic pressure bearing portion for supporting the inner peripheral surface of the sleeve; and a step of polishing the hub and the sleeve. A method of manufacturing a spindle motor, comprising: a step of interfitting; a step of providing the hub with a stopper that prevents the sleeve from moving with respect to the hub; and a step of assembling the rotating member and the stationary member. . 9. A housing, fixed to the inside of the housing according to claims 1 and 5.
9. The spindle motor according to claim 7, or the spindle motor manufactured by the manufacturing method according to claim 2, 3 or 8, and a disk-shaped recording fixed to the rotating member, capable of recording information. A recording disk drive device comprising: a medium; and an information access unit for writing or reading information at a required position on the recording medium.