JP2000069708A - Spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spindle motor which can be priced down and can relatively simply and besides surely keep airtightness between a bracket and a base member on the side of a driver. SOLUTION: This spindle motor is provided with a bracket 2, a rotor hub 4 rotatable to the bracket 2, a circular magnet 28 mounted on the rotor hub 4, and a stator 30 arranged in opposition to the circular magnet 28. The bracket 2 has an attachment part 8 attached to a base member 6 on the side of a driver and a bracket body 10 fixed to the roughly center of the attachment part 8, and the attachment part 8 is made by press processing, and also the bracket body 10 is made by cutting processing, and the attachment part 8 is provided with a seal member 50 for sealing the space to the base member 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor for rotating a recording disk or the like.

[0002]

2. Description of the Related Art For example, a spindle motor for a recording disk drive such as a hard disk includes a bracket mounted on a base member of the drive, and a rotor hub on which the hard disk is mounted, and the rotor hub rotates relative to the bracket. It is freely supported. An annular magnet is mounted on the rotor hub, and a stator is disposed to face the magnet.

[0003]

In such a spindle motor, a head unit (a magnetic head for writing and / or reading information to and from a hard disk) on a drive device side and a hard disk mounted on the spindle motor are provided in a predetermined manner. It is important to maintain the positional relationship, and therefore, it is necessary to accurately mount the spindle motor at a predetermined position on the base member of the drive device. Also, among various components of the spindle motor, machining of a specific portion of the bracket The precision needs to be processed with particularly high precision in order to directly affect the rotation precision of the spindle motor. In the spindle motor, since such processing and assembling requirements exist, the bracket is conventionally formed by cutting.

[0004] In recent years, the price of personal computers has been reduced, and the price of the hard disk drive as a component thereof has also been reduced. Under such economic conditions, the spindle motor is required to be inexpensive, and if the bracket is formed by cutting, the cost requirement cannot be sufficiently satisfied.

In order to satisfy such a demand, it has been proposed to form the bracket by pressing at a low processing cost (Japanese Patent Laid-Open No. Hei 8-27543).
No. 9). However, when the press working is used, it is difficult to machine the bracket with high precision, and when the spindle motor is mounted on the hard disk drive, the space between the base member of the drive and the bracket of the spindle motor is sufficiently kept airtight. Not easy. As a result, surrounding dust, dirt, and the like pass through the space between the base member and the bracket and enter the internal space in the drive device (the internal space is kept clean and contains a hard disk, a magnetic head, and the like). There is a risk of causing a failure such as a crash. In particular, to increase the recording capacity of the hard disk due to the increase in capacity, and to shorten the seek time, the hard disk and head means are arranged close to each other with a spacing of several microns, and the internal space of the hard disk drive requires higher cleanliness. Have been.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the cost of a motor by forming a bracket by press working, and to relatively simply and easily form a gap between a bracket formed by press working and a base member on a drive device side. An object of the present invention is to provide a spindle motor that can reliably maintain airtightness.

[0007]

SUMMARY OF THE INVENTION The present invention provides a bracket, a rotor hub on which a recording disk rotatable relative to the bracket is mounted, an annular magnet mounted on the rotor hub, and an opposed to the annular magnet. A spindle motor, which is mounted on a base member of a recording disk drive and rotates the recording disk, wherein the bracket is mounted on the base member; and A bracket body fixed to a substantially central portion of the portion, wherein the mounting portion is formed by pressing and the bracket body is formed by cutting, and the mounting portion has a portion between the base member and the mounting portion. A sealing member for sealing is provided integrally and concentrically with the rotation axis of the rotor hub. And it features.

According to the present invention, of the mounting portion and the bracket body constituting the bracket, the mounting portion is formed by press working, so that the cost of the motor is reduced. Also, since the seal member is provided concentrically with the rotation axis of the rotor hub at the mounting portion of the bracket, the seal member can reliably seal the space between the base member and the mounting portion. Airtightness can be sufficiently ensured. Furthermore, since the seal member is provided integrally with the mounting portion of the bracket, the seal member is pressed against the base member only by mounting the mounting portion to the base member, and the airtightness between the two can be maintained.

[0009] By mounting the bracket body formed with higher machining accuracy by cutting at substantially the center of the mounting portion, it is possible to reduce the cost of the motor in which the mounting portion is formed by pressing, and to reduce the cost of each member. The concentricity can be maintained at the same level as that of the conventional bracket, and the rotation accuracy of the motor is not impaired.

Further, in the present invention, a plurality of through holes are formed in the mounting portion by pressing at intervals in a circumferential direction, and the seal member is insert-molded in the plurality of through holes. It is characterized by being made of annular rubber. According to the present invention, since a plurality of through-holes are formed in the mounting portion by press working, and a ring-shaped rubber formed by insert molding is provided in the through-hole as a seal member, a relatively simple and inexpensive processing is performed. With such a configuration, the seal member can be provided on the mounting portion. Also,
Since the rubber seal member is pressed against the base member when the mounting portion is mounted on the base member on the drive device side, the seal between the mounting portion and the base member can be easily and reliably sealed.

[0011] In the present invention, the mounting portion may have at least one half-pierced protrusion formed by pressing to be concentric with the rotation axis of the rotor hub. The mounting portion is positioned with respect to the base member by contacting with the base member.

According to the present invention, a half-cutting projection is formed concentrically with the rotation axis of the rotor hub on the mounting portion of the bracket by press working, and the half-cutting projection contacts the base member. Thus, the mounting portion is positioned with respect to the base member, so that the mounting portion can be positioned with respect to the base member with relatively simple and inexpensive processing and configuration.

Further, according to the present invention, the rotor hub includes a hub main body having a disk mounting portion for mounting one of the recording disks, and a hub fitted to an outer peripheral surface of the hub main body and hanging down toward the bracket. And a yoke member,
The magnet formed from a ferrite-based material is mounted on an inner peripheral surface of the yoke member.

According to the present invention, the rotor hub has a hub body having a disk mounting portion for mounting one recording disk, and the outer peripheral surface of the hub body hangs down toward the bracket. Space for accommodating parts constituting a magnetic circuit such as a stator and a magnet inside the motor as compared with a conventional spindle motor for rotating a plurality of recording disks. Therefore, a sufficient driving torque can be obtained even if a magnet formed of a ferrite material which is inexpensive but has a small magnetic flux density can be obtained, thereby reducing the cost of the motor. Can contribute.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a spindle motor according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view showing a first embodiment of a spindle motor according to the present invention, and FIG. 2 is a plan view showing a mounting portion of the spindle motor of FIG.

Referring to FIG. 1, the illustrated spindle motor includes a bracket 2 having a substantially circular outer shape, and a rotor hub 4 rotatable with respect to the bracket 2. This type of spindle motor is used for a hard disk drive, and a bracket 2 is attached to a base member 6 of the hard disk drive as shown in FIG.

The illustrated bracket 2 includes a mounting portion 8 mounted on the base member 6 and a bracket body 10 mounted on an inner peripheral portion of the mounting portion 8. In this embodiment, the inner peripheral portion of the mounting portion 8 is fixed to one end of the bracket main body 10 by caulking one end surface (the lower end surface in FIG. 1) of the bracket main body 10. Details of the mounting portion 8 will be described later.

A through hole extending in the axial direction is formed in the bracket body 10, and one end of the shaft member 12 is fixed to the through hole by, for example, press fitting. The other end of the shaft member 12 projects upward from the bracket body 10 and extends,
A pair of bearings 14, 16
Are mounted, and the rotor hub 4 is rotatably supported via the pair of bearings 14 and 16.

The rotor hub 4 has a hub main body 18 made of, for example, aluminum, and a disk mounting portion 20 on which a hard disk (not shown) as a recording disk is mounted on the upper end of the hub main body 18. Is provided. A bracket 2 is provided on the outer periphery of the lower end of the hub body 18.
An annular mounting projection 24 projecting downwardly is provided integrally, and one end (an upper end in FIG. 1) of an annular yoke member 26 is fixed to the outer peripheral surface of the mounting projection 24 by, for example, press fitting. Have been. An annular magnet 28 is provided on the inner peripheral surface of the yoke member 26, and the end surface (the upper end surface in FIG. 1) of the magnet 28 abuts on the distal end surface of the mounting projection 24 of the hub body 18. And is attached to the yoke member 26.

A stator 30 is disposed facing the magnet 28. The stator 30 has a stator core 32 formed by stacking core plates, and a coil 34 wound around the stator core 32 as required. The stator core 32 is pressed into the outer peripheral surface of the bracket body 10 by, for example, press-fitting. Fixed. FIG.
, A cap member 36 is disposed axially outside the upper bearing 16. The cap member 36 is the hub body 1
8 is fixed to the upper end of the hub body 8 by, for example, an adhesive, and seals the upper end opening of the hub body 18 (the upper end opening of the through hole for mounting the bearings 14 and 16).

In this spindle motor, the stator 30
When a driving current is supplied to the coil 34 as required, the rotor hub 4 is driven to rotate in a predetermined direction by the mutual magnetic action of the magnetized stator core 32 and the magnet 28, and a hard disk (not shown) is integrally formed with the rotor hub 4. Is rotated.

The illustrated spindle motor also has the following structural features. That is, the disk mounting part 20 is provided at the upper end of the hub main body 18, and one hard disk can be mounted on the disk mounting part 20. In this way, by dedicating the configuration of the hub body 18 to one hard disk, the hub body 18 can be made smaller. As a result, when the overall height of the motor is constant, the yoke member 2
A relatively large space for the magnetic circuit can be ensured radially inward of 6. This makes it possible to increase the size of the magnetic circuit components and to obtain a large driving torque. In other words, it is possible to use a material having a low magnetic flux density and a small coercive force, for example, a ferrite-based material as the magnet 28, and the material of the magnet 28 can be selected in a wide range. By using (material), the manufacturing cost can be kept low, and the cost of the motor can be reduced.

Next, with reference to FIG. 2 together with FIG. 1, the mounting portion 8 and its related structure will be described. The illustrated mounting portion 8 is formed by pressing a substantially circular plate-shaped member, for example, a plate-shaped member having a thickness of about 0.4 mm to 1.6 mm (this plate-shaped member is also formed by pressing). Thereby, it is formed into the shape shown in FIGS. By forming the mounting portion 8 by press working, the processing cost of the mounting portion 8 is reduced, and the manufacturing cost of the motor can be reduced.

The mounting portion 8 formed by pressing is
A bottom wall portion 42 caulked to the bracket body 10,
A peripheral wall portion 44 extending upward from an outer peripheral portion of the bottom wall portion 42
And a flange portion 46 protruding radially outward from the upper end of the peripheral wall portion 44. The flange portions 46 are provided at substantially equal intervals in the circumferential direction (in this embodiment, 120 ° intervals are provided). (Placed) three mounting holes 48 are provided. Since the mounting portion 8 is formed from a plate-like member, these mounting holes 48 can also be formed by pressing, and by forming by pressing, the processing cost can be reduced.

The mounting portion 8 further includes an annular sealing member 5.
0 is provided integrally. In this embodiment, the inner peripheral portion of the flange portion 46 of the mounting portion 8, specifically, the mounting hole 48
In the part radially inner than the part where is formed,
A plurality (six in this embodiment) of through-holes 52 are formed at intervals in the circumferential direction, and each through-hole 52 is elongated in the circumferential direction and extends like a slit. By forming these through holes 52 by press working, the processing cost can be suppressed, and by working simultaneously with the mounting holes 48, the number of processing steps can be reduced.

The seal member 50 has a part thereof formed with a through hole 52.
It is fixed integrally to. In this embodiment, the seal member 50 is formed of rubber having elasticity, and is formed by filling the through holes 52 with a rubber material and performing insert molding. By performing insert molding in this manner, the seal member 50 can be easily provided on the mounting portion 8 concentrically with the rotation axis of the rotor hub 4 (extending in the vertical direction in FIG. 1). When the seal member 50 is provided as shown in FIG. 1, one side portion 54 is annularly provided on the inner surface (the upper side surface in FIG. 1) of the flange portion 46 through the through hole 52, while the other side portion 56 is provided with the through hole. An annular surface is provided on the outer surface (lower side surface in FIG. 1) of the flange portion 46 through the both sides 52, and both side portions 54, 56 are connected via a part of the seal member 50 in the through hole 52. It is securely fixed to the mounting portion 8 with a relatively simple configuration.

The spindle motor provided with the mounting portion 8 is mounted on the base member 6 of the hard disk drive as follows. A circular opening 58 for mounting a spindle motor is formed in the base member 6, and the peripheral wall portion 44 of the mounting portion 8 is inserted into the opening 58 from the inside of the driving device and positioned at a predetermined position. Mounting screw (not shown) through each mounting hole 48 of the mounting portion 8
Is screwed to the base member 6 to attach the spindle motor to the base member 6. In such an attached state, as understood from FIG. 1, the other side portion 56 of the seal member 50 is interposed between the flange portion 46 of the attachment portion 8 and the base member 6. The other side portion 56 is annularly located outside the opening 58 of the base member 6 in the radial direction, so that the space between the bracket 2 and the base member 6 is reliably sealed, and the airtightness between the two members can be enhanced. . Further, since the seal member 50 is provided integrally with the mounting bracket 2, the seal member 50 is pressed against the base member 6 by simply attaching the motor to the base member 6, and the airtightness between the two can be ensured. Further, since the seal member 50 is interposed between the bracket 2 of the motor and the base member 6, it has an effect of suppressing vibration transmitted from the motor to the base member 6.

In the embodiment described above, the through hole 52 is provided in the bracket 2 and the seal member 50 is integrally provided by insert molding using the through hole 52. However, when the seal member 50 can be securely fixed. A concave portion may be provided at a predetermined portion of the bracket 2 and a seal member may be provided by insert molding using the concave portion.

FIG. 3 is a sectional view showing a second embodiment of the spindle motor according to the present invention. In the second embodiment, a positioning structure for positioning the motor with respect to the base member on the driving device side is added.
In the second embodiment, members that are substantially the same as those in the first embodiment shown in FIGS. 1 and 2 are given the same reference numerals, and descriptions thereof are omitted.

Referring to FIG. 3, in the second embodiment, a bracket 2A of a spindle motor is provided with a mounting portion 8A mounted on a base member 6A of a hard disk drive.
And a bracket body 10 mounted on the inner peripheral portion of the mounting portion 8A. The mounting portion 8A is formed by pressing a plate-shaped member. That is, by further performing press working on a circular plate-shaped member formed by stamping of press working, the mounting portion 8A as shown in FIG. 3 is formed.

At a predetermined portion on the inner surface (upper surface in FIG. 3) of the mounting portion 8A, in this embodiment, a portion radially inward from the portion where the mounting hole 48 is formed, an arc-shaped half blanking protrusion is formed by pressing. At least one portion 60 (a protrusion formed by punching about half and plastically deforming, instead of completely punching by press working) is provided in the circumferential direction.

In this embodiment, when the spindle motor is fixed to the driving device, the inner peripheral surface of the opening 58 of the base member 6A is brought into contact with the outer peripheral surface of the half-punched projection 60, so that the spindle motor 6A is located at a predetermined position. Then, in this state, by attaching a mounting screw (not shown) to the base member 6A through each mounting hole 48, the motor is mounted as required. In this mounting state, the seal member 50 is pressed against the base member 6A as in the first embodiment described above, and the base member 6A is pressed.
The space between A and the bracket 2A of the motor is sealed, and sufficient airtightness between them is ensured. Also, the half blanking protrusion 6
Since 0 is formed by press working, it can be formed relatively easily and at low processing cost, and the man-hours for manufacturing the motor can be reduced, so that the manufacturing cost of the motor can be reduced.

In this embodiment, the hub body 18A
The annular mounting projection 24 provided at the lower end of the disk mounting portion 20 is provided somewhat radially inward from the outer peripheral end of the disk mounting portion 20.
Is mounted on the outer peripheral surface of the mounting projection 24 so that the upper end thereof contacts the lower surface of the disk mounting portion 20. Other configurations of the second embodiment are substantially the same as those of the first embodiment.

FIG. 4 is a sectional view showing a third embodiment of the spindle motor according to the present invention. In the first and second embodiments, the present invention is applied to a fixed shaft type motor. In the third embodiment, the present invention is applied to a fixed shaft type motor. In the third embodiment, members that are substantially the same as those in the first embodiment shown in FIGS. 1 and 2 are given the same reference numerals, and descriptions thereof are omitted.

Referring to FIG. 4, in the third embodiment, a bracket 2B of a spindle motor is provided with a mounting portion 8B mounted on a base member 6B of a hard disk drive.
And a bracket body 10B mounted on the inner peripheral portion of the mounting portion 8B. The mounting portion 8B is formed by pressing a plate-shaped member, and the bracket body 10B is formed by cutting. A support sleeve portion 72 is provided integrally with the bracket body 10B. A shaft member 12B is fixed to the rotor hub 4B, and the shaft member 12B is rotatably supported by the support sleeve portion 72 via a pair of bearings 14 and 16.

Also in this embodiment, the seal member 50 is provided by filling a through-hole with a rubber material and insert-molding the same as in the first embodiment. By performing the insert molding in this manner, the rotation axis of the rotor hub 4B (the axis indicated by a one-dot chain line extending vertically in FIG. 4).
The seal member 50 can be easily provided concentrically on the mounting portion 8B.

Also in the third embodiment, when the spindle motor is mounted on the base member 6B of the driving device, the seal member 50 is pressed against the base member 6B as in the first embodiment, and the base member 6B The space between the motor and the bracket 2B is sealed, and sufficient airtightness between them is ensured.

In this embodiment, the hub body 18B
An annular mounting protrusion 24 having an inverted L-shaped cross section is provided at the lower end of the disc mounting portion 20.
Hanging towards. The yoke member 26 is mounted on the inner peripheral surface of the mounting protrusion 24 so as to contact the inner surface of the mounting protrusion 24 (a surface that defines the same surface as the lower surface of the disk mounting portion 20). Other basic configurations of the second embodiment are as follows.
This is substantially the same as the first embodiment.

The embodiment of the spindle motor according to the present invention has been described above. However, the present invention is not limited to such an embodiment, and various changes and modifications can be made without departing from the scope of the present invention. . For example, in the illustrated embodiment, the description has been made by applying the present invention to a motor using a ball bearing as a bearing. However, the present invention is not limited to this, and may be similarly applied to a motor using a hydrodynamic bearing as a bearing. it can.

[0040]

According to the spindle motor of the first aspect of the present invention, the motor is reduced in price by forming the mounting portion of the bracket by press working, and the seal provided integrally with the mounting portion of the bracket. The member can reliably seal the space between the base member and the mounting portion on the recording disk drive device side, and the airtightness between the two can be sufficiently maintained. Further, the airtightness between the two can be maintained only by attaching the bracket to the base member.

According to the spindle motor of the second aspect of the present invention, the seal member can be provided on the mounting portion of the bracket with a relatively simple and inexpensive processing and configuration. Further, since the rubber seal member is pressed against the base member when the mounting portion is mounted on the base member on the drive device side, the space between the mounting portion and the base member can be easily and reliably sealed.

According to the spindle motor of the third aspect of the present invention, the mounting portion of the bracket can be positioned with respect to the base member of the driving device with relatively simple and inexpensive processing and configuration. And the manufacturing cost can be reduced.

Further, according to the spindle motor of the fourth aspect of the present invention, a relatively large space for the magnetic circuit can be secured inside the yoke member, so that an inexpensive ferrite magnet can be used. However, a sufficient driving torque can be obtained, and the cost of the motor can be further reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a spindle motor according to the present invention.

FIG. 2 is a plan view showing a mounting portion of a bracket of the spindle motor shown in FIG. 1;

FIG. 3 is a sectional view showing a second embodiment of the spindle motor according to the present invention.

FIG. 4 is a sectional view showing a third embodiment of the spindle motor according to the present invention.

[Explanation of symbols]

 2, 2A, 2B Mounting bracket 4, 4A, 4B Rotor hub 6, 6A, 6B Base member 8, 8A, 8B Mounting portion 10, 10A, 10B Bracket body 18, 18A, 18B Hub body 26 Yoke member 28 Magnet 30 Stator 50 Seal Member 52 Through-hole 60 Half blanking protrusion

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H019 AA09 AA10 CC04 FF03 5H605 AA03 BB05 CC02 CC05 CC10 DD36 EA09 FF08 GG12 GG14 5H621 JK07 JK10 JK13

Claims (4)

[Claims] 1. A bracket, a rotor hub on which a recording disk rotatable relative to the bracket is mounted, an annular magnet mounted on the rotor hub, and a stator disposed to face the annular magnet. A spindle motor attached to a base member of a recording disk drive device for driving the recording disk to rotate, wherein the bracket is fixed to an attachment portion attached to the base member and to a substantially central portion of the attachment portion. A bracket body formed by pressing, the bracket body is formed by cutting, and the mounting portion includes a sealing member for sealing between the mounting portion and the base member. A spindle motor provided integrally and concentrically with the rotation axis of the rotor hub. Data. 2. A plurality of through holes are formed in the mounting portion by pressing at intervals in a circumferential direction, and the seal member is formed of an annular rubber insert-molded into the plurality of through holes. The spindle motor according to claim 1, wherein 3. The mounting portion, wherein at least one half blanking projection is formed concentrically with the rotation axis of the rotor hub by press working, and the half blanking projection contacts the base member. The spindle motor according to claim 1, wherein the mounting portion is positioned with respect to the base member by the operation. 4. A rotor body having a disk mounting portion for mounting one recording disk, a yoke member fitted on an outer peripheral surface of the hub body and hanging down toward the bracket. Wherein the magnet formed of a ferrite-based material is mounted on an inner peripheral surface of the yoke member.
The spindle motor according to any one of the above.