JP2000262006A - Disc drive motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a disc drive motor which has improved structure including a frame and its surroundings, in order to achieve the cost reduction. SOLUTION: A frame 20 of a rotary shaft type disc drive motor 1A is a stamping manufactured by applying stamp to a steel plate, etc. Therefore, the finish with the inner diameter, out-of-roundness, etc., of a bearing retaining part 21, which have certain quality level or higher which cannot be obtained without secondary machining when casting, can be obtained. The thickness of the bearing retaining part 21 is not larger than 0.8 times the thickness of the bottom part 23 of the frame 20, and further, is not smaller than the maximum thickness of the outer rings 15A and 17A of ball bearings 15 and 17. With this constitution, even of accuracy of the inner diameter and out-of- roundness of the bearing retaining part 21 is relatively low, when the ball bearings 15 and 17 are accommodated in the retaining part 21, the bearing retaining part 21 may be distorted but the ball bearings 15 and 17 are never distorted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive motor for rotating a recording disk such as a hard disk. More specifically, the present invention relates to a structure of a frame and its peripheral portion in this type of motor.

[0002]

2. Description of the Related Art As a disk drive motor for rotating a recording disk such as a hard disk, a shaft rotation type in which a disk mounting hub rotates together with a rotating shaft, and a disk mounting hub using a ball bearing There is a fixed shaft type rotatably supported on a fixed shaft via a shaft. Conventionally, all of these types of motors are configured on a frame made of aluminum die-cast.

For example, a disk drive motor 1D shown in FIG. 4 is a shaft rotation type motor, and a rotation shaft 113 extending downward from a disk mounting hub 111 and rotatably supports the rotation shaft 113. And a pair of ball bearings 115, 117
Cylindrical bearing holding portion 12 for holding 117 inside
Frame 1 protruding from bottom 123, and stator core 1 held on the outer peripheral side of bearing holding portion 121
30 and a coil 135 wound around the stator core 130.
The hub 111 includes a stator core 1
An annular rotor magnet 112 is fixed via a yoke 114 so as to face the unit 30. An annular protrusion 125 protrudes into the bearing holding portion 121,
The end faces of the outer races 115A and 117A of the upper and lower ball bearings 115 and 117 are brought into contact with the annular projection 125, so that the ball bearing 11 is formed.
5 and 117, and a preload is applied to the ball bearings 115 and 117.

In the disk drive motor 1D shown here, both the frame 120 and the hub 111 are aluminum die-cast products, and after forming a blank by casting or the like, dimensional accuracy is obtained by secondary processing such as cutting. For example, in the frame 120, if the inner diameter of the bearing holding portion 121, roundness, or smoothness of the inner peripheral surface is low, the ball bearing 11
When the outer races 115A and 117A are mounted, an excessive force is applied to the outer races 115A and 117A, and the ball bearings 115 and 117 are attached.
May be distorted. When such distortion occurs, the rotation shaft 113 cannot be held vertically, and the NRRO characteristics of the motor deteriorate. Therefore, conventionally, when manufacturing the frame 120 by die-casting, dimensional accuracy is obtained by cutting the inner peripheral surface of the bearing holding portion 121 by secondary processing.

[0005]

However, in spite of the strong demand for lowering the cost of the disk drive motor 1D, the conventional method for manufacturing the frame 120 requires a casting step and a cutting step. And the like, there is a problem that the cost of the frame 120 itself is high and the cost of the motor cannot be reduced. Such a problem is not limited to a shaft rotation type motor, but also applies to a fixed shaft type motor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a disk drive motor capable of responding to cost reduction by improving the structure of a frame and its peripheral portion.

[0007]

According to the present invention, there is provided a rotating shaft extending downward from a hub for mounting a recording disk, and a pair of balls for rotatably supporting the rotating shaft. A bearing, a frame in which a cylindrical bearing holding portion for holding the pair of ball bearings inside protrudes from the bottom, a stator core held on the outer peripheral side of the bearing holding portion, and a coil wound on the stator core. In a disk drive motor having an annular rotor magnet mounted on the hub so as to face the stator core, the frame is formed by pressing a plate material such that the bearing holding portion protrudes in a cylindrical shape. It is characterized by being composed of a pressed product.

In the present invention, the frame is a pressed product manufactured by subjecting a steel plate or the like to press working. If such a pressed product is used, the frame is subjected to secondary processing unlike a cast product. Even if it is not provided, the bearing holding portion can be finished with a certain quality or higher in inner diameter, roundness, or inner surface smoothness. Therefore, there is no need to perform a complicated casting step or a secondary processing step, so that the frame can be manufactured at low cost. Also, material costs can be reduced. Therefore,
The cost of the disk drive motor can be reduced.

In the present invention, a thickness of the bearing holding portion is 0.8 times or less of a thickness of a bottom portion of the frame, and is smaller than a maximum thickness of an outer ring of the ball bearing. preferable. In this way, if the thickness of the bearing holding portion is reduced to some extent, even if the accuracy of the inner diameter and roundness of the bearing holding portion is somewhat low, when the ball bearing is mounted inside the bearing holding portion, Even if the bearing holding part side is distorted, the ball bearing is not distorted. Therefore, even if the cost of the motor is reduced by forming the frame by a pressed product, the ball bearing can maintain good motor characteristics such as supporting the rotating shaft vertically.

[0010] In the present invention, it is preferable that an annular pedestal having a step formed on an outer peripheral side is mounted on an outer peripheral surface of the bearing holding portion, and a stator core is held on the step of the pedestal. In the present invention, since the frame is manufactured by pressing the plate material, there is no thick portion. As described above, it is advantageous to form the bearing holding portion to some extent thinner from the viewpoint of selecting a motor. Therefore, it is difficult to form a step on which the stator core can be placed on the outer peripheral surface of the bearing holding portion. However, a ring-shaped pedestal is mounted on the bearing holding portion, and the step formed on the outer peripheral side is attached to the mounting portion of the stator core. By using this, it is possible to solve the problem that it is difficult to form a step for mounting the stator core on the outer peripheral surface of the bearing holding portion.

The present invention is not limited to the rotary shaft type, and can be applied to a fixed shaft type disk drive motor. That is, in another embodiment of the present invention, a frame in which a cylindrical shaft holding portion protrudes from the bottom, a fixed shaft held by the shaft holding portion, and a pair of ball bearings held by the fixed shaft,
A recording disc mounting hub rotatably supported on the fixed shaft via the pair of ball bearings, a stator core held on an outer peripheral side of the shaft holding portion, and a coil wound around the stator core. A disk drive motor having an annular rotor magnet mounted on the hub so as to face the stator core, wherein the frame is formed by pressing a plate material such that the shaft holding portion protrudes in a cylindrical shape. It is characterized by being composed of a pressed product.

Also in the present invention, the frame is a pressed product manufactured by subjecting a steel plate or the like to press working. If such a pressed product is used, unlike a cast product, the frame is subjected to secondary processing. Even if it is not performed, the inner diameter of the shaft holding portion, the roundness and the like are finished with a certain quality or higher. Therefore, there is no need to perform a complicated casting step or a secondary processing step, so that the frame can be manufactured at low cost. Also, material costs can be reduced. Therefore, the cost of the disk drive motor can be reduced.

In the present invention, an annular step may be formed on an outer peripheral side of the shaft holding portion, and the stator core may be held on the step. In the case of such a fixed shaft type, unlike a rotary shaft type motor, the shaft holding portion may be formed to be somewhat thick, so that a step is formed on the outer peripheral surface of the shaft holding portion. The steps may be used for mounting the stator core.

Further, in the present invention, an annular pedestal having a step formed on the outer peripheral side may be mounted on an outer peripheral surface of the shaft holding portion, and a stator core may be held on the step of the pedestal.

[0015] In the present invention, the pedestal may be provided between an outer ring of a ball bearing disposed below the pair of ball bearings, and a lower end of a cylindrical bearing holding portion protruding downward from the hub. It is preferable to form a minute gap forming a labyrinth seal between them. That is, when a pressed product is used as the frame, since there is no thick portion, it is difficult to form a minute gap forming the labyrinth seal by using the thick portion. If a separate ring-shaped member called a pedestal is used as described above, a minute gap forming a labyrinth seal can be formed using the pedestal.

In the present invention, the pedestal is preferably made of plastic in both the rotating shaft type and the fixed shaft type. With such a pedestal, the vibration when the hub rotates is less likely to be transmitted to the stator core, so that the rotational performance of the motor is improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a disk drive according to the present invention will be described with reference to the drawings.

[First Embodiment] FIG. 1 is a half sectional view showing a disk driving motor according to a first embodiment of the present invention.

In FIG. 1, a disk drive motor 1A according to the present embodiment includes a rotating shaft 13 extending downward from a hub 11 for mounting a recording disk, and a pair of ball bearings 15 rotatably supporting the rotating shaft 13. , 17 and a frame 2 having a cylindrical bearing holding portion 21 for holding these ball bearings 15, 17 inside from a bottom portion 23.
0, the stator core 30 held on the outer peripheral side of the bearing holding portion 21, the coil 35 wound around the stator core 30, and the hub 1 so as to face the stator core 30.
1 and a ring-shaped rotor magnet 12 mounted thereon.

In this embodiment, the frame 20 is formed of a pressed product obtained by pressing a plate material such as a steel plate so that the bearing holding portion 21 protrudes in a cylindrical shape. The upper and lower ball bearings 15 and 17 are mounted in the bearing holding portion 21 so as to be positioned vertically above and below the ring-shaped spacer 25. The outer rings 15A and 17A of these ball bearings 15 and 17 are It is adhesively fixed to the inner peripheral surface of the bearing holding portion 21.

A connector 39 for supplying power to the coil 35 wound around the stator core 30 is provided near the bearing holding portion 21 on the bottom portion 23 of the frame 20.
Is mounted, and a terminal of the coil 35 (not shown).
Are electrically connected to a flexible wiring board and lead wires (not shown) on the connector 39.

On the outer peripheral side of the frame 20, there is formed a flange portion 29 which is fixed to a chassis of an information recording apparatus or the like on which the motor is mounted by screws or the like.

In the present embodiment, since the frame 20 is a pressed product, there is no extremely thin or thick portion as a whole, but the thickness t1 of the bearing holding portion 21 is not limited to the bottom portion 23 of the frame 20. 0.8 for the wall thickness t2 of
And the ball bearings 15, 17
Are set to be thinner than the maximum thickness t3 of the outer rings 15A and 17A.

Further, since the frame 20 is a press-processed product, there is a restriction that the bearing holding portion 21 cannot be formed thick, and in the present embodiment, as described above, the bearing holding portion 21 is Bottom 23 of
And the outer rings 15A and 17A of the ball bearings 15 and 17 are made thinner. For this reason, a step or the like on which the stator core 30 is placed cannot be formed on the bearing holding portion 21 itself.
A plastic pedestal 40 having a step 41 on the outer peripheral side is attached to an outer peripheral surface of the pedestal 40.
1, the stator core 30 is mounted. The stator core 30 arranged in this manner is fixed by the adhesive 50 applied from the outer peripheral surface of the bearing holding portion 21 to the upper end of the pedestal 40.

In this embodiment, the hub 11 is a cup-shaped aluminum die-cast product having an opening directed downward, and the upper end of the rotating shaft 13 is fitted into a central hole 16 formed in a central portion having a considerably large thickness. It is fixed. Also,
The outer peripheral surface of the rotating shaft 13 is
Inner ring 15 of ball bearings 15 and 17 arranged in
B and 17B are adhesively fixed. Further, the rotating shaft 13
Of the ball bearing 17 in the lower position
A cap 55 is bonded and fixed to the outer end surface of B, so that the rust preventive used for the ball bearings 15 and 17 does not scatter.

An annular projection 17 is formed on the lower surface of the hub 11 so as to protrude downward around the central hole 16. The annular projection 17 abuts on the upper end surface of the inner ring 15 B of the upper ball bearing 15. A preload is applied to the ball bearing 15 so as to hold down the ball bearing 15B.

A plurality of steps are formed on the upper surface side of the hub 11, and the step surface on the outer peripheral side is a disk mounting surface 18. A screw for fixing a clamp member (not shown) for fixing a hard disk mounted on the disk mounting surface 18 is provided on a step surface formed on the inner peripheral side of the disk mounting surface 18. A hole 110 is formed. A hole 119 is formed on the back side of the step surface where the screw hole 110 is formed in order to adjust the rotational balance of the hub 11.

In the hub 11, a cylindrical side surface portion 119 extends downward from the outer peripheral side of the disk mounting surface 18. The rotor magnet 12 is fixed to the inner peripheral surface of the cylindrical side surface portion 119 via the yoke 14, and the rotor magnet 12 is in a state of facing the outer peripheral surface of the stator core 30.

In the disk drive motor 1A configured as described above, in this embodiment, the frame 20 is a pressed product manufactured by pressing a steel plate or the like. For example, unlike a cast product, even if secondary processing is not performed, the bearing holding portion 21 can be finished with a certain quality or higher in inner diameter, roundness, or inner surface smoothness. Therefore, there is no need to perform a complicated casting step or a secondary processing step, so that the frame 20 can be manufactured at low cost. Also, material costs can be reduced. Therefore, the cost of the disk drive motor 1A can be reduced.

The thickness t1 of the bearing holding portion 21
Is 0.8 with respect to the thickness t2 of the bottom portion 23 of the frame 11.
And less than the maximum thickness t3 of the outer rings 15A, 17A of the ball bearings 15, 17. As described above, since the thickness t1 of the bearing holding portion 21 is reduced to some extent, even if the accuracy of the inner diameter and roundness of the bearing holding portion 21 is slightly lower, the ball bearings 15 and 17 are provided inside the bearing holding portion 21. When the ball bearing 1 is mounted, even if the bearing holding portion 21 side is distorted,
The outer races 15A and 17A of 5 and 17 are not distorted. Therefore, even if the cost of the motor is reduced by forming the frame 20 by a pressed product, it is possible to maintain good motor characteristics such as the ball bearings 15 and 17 supporting the rotating shaft 13 vertically.

Further, in this embodiment, since the frame 20 is manufactured by pressing a plate material, there is no thick portion.
Further, as described above, it is advantageous from the viewpoint of motor characteristics that the bearing holding portion 21 is formed to be thin to some extent. Therefore, it is difficult to form a step on which the stator core 30 can be placed on the outer peripheral surface of the bearing holding portion 21. However, the ring-shaped pedestal 40 is mounted on the bearing holding portion 21, and the step 41 formed on the outer peripheral side is formed. Stator core 30
Since it is used as a mounting portion, the problem that it is difficult to form a step for mounting the stator core on the bearing holding portion 21 of the frame 20 formed by press working can be solved.

Moreover, since the pedestal 40 is made of plastic, even if vibrations generated when the hub 11 rotates are transmitted to the pedestal 40 via the rotating shaft 13 and the ball bearings 15 and 17, such vibrations are transmitted to the pedestal 40. Can be absorbed. Accordingly, since vibration is not easily transmitted to the stator core 30, there is an advantage that the rotational performance of the motor is stable.

[Second Embodiment] FIG. 2 is a half sectional view showing a disk driving motor according to a second embodiment of the present invention. The disk drive of this embodiment is of a fixed-shaft type, but has portions common to the first embodiment. Therefore, corresponding portions are denoted by the same reference numerals.

In FIG. 2, the disk drive motor 1B of this embodiment comprises a frame 20 having a cylindrical shaft holding portion 22 protruding from a bottom portion 23, a fixed shaft 19 held by the shaft holding portion 22, and a fixed shaft 19. 19, a pair of ball bearings 15, 17 held by
17, a recording disk mounting hub 11 rotatably supported on a fixed shaft 19, a stator core 30 held on the outer peripheral side of a shaft holding portion 22, and a coil 35 wound around the stator core 30. , An annular rotor magnet 1 mounted on the hub 11 so as to face the stator core 30
2 is roughly constituted.

In this embodiment, the frame 20 is formed of a pressed product obtained by pressing a plate material such as a steel plate so that the shaft holding portion 22 protrudes in a cylindrical shape.

On the bottom portion 23 of the frame 20, near the shaft holding portion 22, a connector 39 for supplying power to the coil 35 wound around the stator core 30 is mounted. An outer peripheral side of the frame 20 is formed with a flange portion 29 which is fixed to a chassis of an information recording device or the like on which the motor is mounted by screws or the like.

In this embodiment, since the frame 20 is a press-processed product, there is no extremely thin or thick portion as a whole, but the thickness of the shaft holding portion 22 is larger than the thickness of the bottom portion 23. Although it is thin, unlike the bearing holding portion of the first embodiment, it can be formed to be slightly thicker.
A step 220 on which the stator core 30 is placed is formed, and the stator core 30 pressed into the shaft holding section 22 is held on the step 220.

In this embodiment, the hub 11 is also a cup-shaped press-formed product in which a plate material such as a steel plate is pressed so that the opening faces downward.

In the hub 11, a cylindrical bearing holding portion 100 protrudes downward from a central portion thereof. The ball bearings 15 and 17 are vertically arranged in the bearing holding portion 100 with an annular spacer 25 interposed therebetween.
7A is adhesively fixed to the inner peripheral surface of the bearing holding portion 100. The spacer 25 used here is used as an outer ring of a ball bearing. For this reason,
There is an advantage that it has high accuracy in the thickness dimension and the like and is inexpensive because other parts are diverted. Further, the outer races 15A and 17A of the upper and lower ball bearings 15 and 17 and the spacer 25 are all formed of the same bearing steel, and therefore have the same thermal expansion coefficient. Therefore, even if there is a temperature change, the outer rings 15A, 17A of the upper and lower ball bearings 15, 17
Since the spacers 25 expand and contract in the same manner, the preload applied to the ball bearings 15 and 17 does not change.

A fixed shaft 19 is inserted inside the ball bearings 15, 17, and the inner rings 15 B, 15 B of the ball bearings 15, 17 are attached to the outer peripheral surface of the fixed shaft 19.
17B is adhesively fixed. Here, the upper ball bearing 15 is in a state of protruding from the upper end surface of the hub 11, and at a position above the fixed shaft 19, the side surface portion 560 extends from the outer end surface of the outer ring 15A of the ball bearing 15 to the outer peripheral surface. The attached cap 56 is adhered and fixed, so that the rust preventive used for the ball bearings 15 and 17 is not scattered. Here, the adhesive 58 is applied to the side surface 560 of the cap 56 and the outer ring 15 of the ball bearing 15.
Since the coating is applied across the outer peripheral surface of A and the upper end surface of the hub 11, the adhesive strength of the cap 56 is high.

The hub 11 is a press-processed product, and its upper surface is formed with a plurality of steps, similar to a conventional hub, and the step surface on the outer peripheral side is a disk mounting surface 18. A screw hole 110 for fixing a clamp member (not shown) for fixing a hard disk mounted on the disk mounting surface is formed on a step surface formed inside the disk mounting surface 18. Is formed. However, hub 1
1 is a pressed product, so that there is no thick portion enough to form a hole for adjusting the rotational balance of the hub 11. Therefore, in the present embodiment, the ring-shaped balance adjustment piece 70 is bonded and fixed using a concave portion formed inside the hub 11, and a hole 71 is formed in the balance adjustment piece 70, thereby rotating the hub 11. The balance can be adjusted.

In the hub 11 as well, the cylindrical side surface portion 119 extends downward from the outer peripheral side of the disk mounting surface 18.
Is extending. The rotor magnet 12 is fixed to the inner peripheral surface of the cylindrical side surface portion 119.
Is in a state of facing the outer peripheral surface of the stator core 30.

In the disk drive motor 1B thus configured, in the present embodiment, the frame 20 is a pressed product manufactured by pressing a steel plate or the like. For example, unlike a cast product, even if secondary processing is not performed, the shaft holding portion 22 can be finished with a certain or higher quality in terms of inner diameter, roundness, and the like. Therefore, there is no need to perform a complicated casting step or a secondary processing step, so that the frame 20 can be manufactured at low cost.
Also, material costs can be reduced. Therefore, the cost of the disk drive motor 1B can be reduced.

In the case of the fixed shaft type, unlike the shaft rotation type motor (Embodiment 1), no ball bearing is mounted inside the frame 20. It may be formed thick. Therefore,
Since the step 220 can be formed on the outer peripheral surface of the shaft holding portion 22, the step 220 can be used for mounting the stator core.

Further, in this embodiment, the hub 11 is also manufactured by pressing the plate material, so that the cost of the motor can be further reduced. Moreover, since the hub 11 manufactured by press working has no thick portion, there is no place where a hole for adjusting the rotational balance can be formed, but instead, the entire hub 11 is thin, so that the balance is The attachment of the adjustment piece 70 does not prevent the motor from being downsized. Therefore, it is possible to adjust the rotational balance of the hub 11 by making a hole 70 in the balance adjusting piece 70 attached to the inside of the hub 11, and to maintain a favorable rotational balance even with the hub 11 manufactured by press working. .

[Modification of Second Embodiment] FIG. 3 is a half sectional view showing a disk drive motor according to a modification of the second embodiment of the present invention. It should be noted that the disk drive motor of the present embodiment has almost the same basic configuration as that of the second embodiment, and the corresponding parts are denoted by the same reference numerals and description thereof will be omitted.

In FIG. 3, the disk driving motor 1C of the present embodiment also has a cylindrical shaft holder 2 similar to the second embodiment.
The frame 20 from which the base 2 protrudes from the bottom 23 and the shaft holding unit 2
2, a pair of ball bearings 15 and 17 held by the fixed shaft 19, and a recording disk mounted rotatably supported by the fixed shaft 19 via these ball bearings 15 and 17. Mounting stator 11, a stator core 30 held on the outer peripheral side of the shaft holding part 22, a coil 35 wound around the stator core 30, and an annular rotor mounted on the hub 11 so as to face the stator core 30. And a magnet 12.

Also in the present embodiment, the frame 20 and the hub 11 are formed by pressing a plate material such as a steel plate so that the shaft holding portion 22 and the bearing holding portion 100 protrude in a cylindrical shape. .

In this embodiment, since the thickness of the shaft holding portion 22 is designed to be thin, the stator core 3 is attached to the shaft holding portion 22 itself.
Although a step for mounting 0 cannot be formed, in this embodiment,
A plastic pedestal 40 having a step 41 on the outer peripheral side is press-fitted and fixed to the outer peripheral surface of the shaft holding portion 22, and the stator core 30 press-fitted and fixed to the pedestal 40 is mounted on the step 41 of the pedestal 40. I have. Therefore, even if the frame 20 is formed of a pressed product, the stator core 30
There is no hindrance to the retention. In addition, since the pedestal 40 is made of plastic, even if vibrations when the hub 11 rotates are transmitted to the pedestal 40 via the fixed shaft 19 and the shaft holding portion 22, such vibrations can be absorbed by the pedestal 40. Can be. Accordingly, since vibration is not easily transmitted to the stator core 30, there is an advantage that the rotational performance of the motor is stable.

Further, in this embodiment, the cylindrical portion 44 extends upward from the pedestal 40, and the cylindrical portion 44 projects between the outer ring 17 A of the lower ball bearing 17 and the hub 11 downward. Bearing holding part 10
Small gaps 73 and 74 that form a labyrinth seal are formed between the lower end of the zero and the lower end. Therefore, when a pressed product is used as the frame 20, since there is no thick portion, it is difficult to form a minute gap forming the labyrinth seal using this thick portion. If a ring-shaped separate member called the pedestal 40 is used as described above, the pedestal 40 can be used to form the minute gaps 73 and 74 constituting the labyrinth seal.

[0051]

As described above, according to the present invention, in a shaft-rotating type or fixed-shaft type disk driving motor, the frame is a pressed product manufactured by pressing a steel plate or the like. . Therefore, unlike a cast product, even if secondary processing is not performed, the bearing holding portion and the shaft holding portion can be finished with a certain degree of inner diameter and roundness. Therefore, there is no need to perform a complicated casting step or a secondary processing step, so that the frame can be manufactured at low cost. Also, material costs can be reduced. Therefore, the cost of the disk drive motor can be reduced.

In the shaft-rotating disk drive motor, the thickness of the bearing holding portion is 0.8 times or less the thickness of the bottom portion of the frame, and is smaller than the maximum thickness of the outer race of the ball bearing. Then, even if the accuracy of the inner diameter and the roundness of the bearing holding portion is somewhat low, even if the bearing holding portion side is distorted when the ball bearing is mounted inside the ball holding portion, the ball bearing is not distorted. Therefore, even if the cost of the motor is reduced by forming the frame by a pressed product, the ball bearing can maintain good motor characteristics such as supporting the rotating shaft vertically.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a disk drive motor according to a first embodiment of the present invention.

FIG. 2 is a half sectional view of a disk drive motor according to a second embodiment of the present invention.

FIG. 3 is a half sectional view of a disk drive motor according to an improved example of the second embodiment of the present invention.

FIG. 4 is a half sectional view of a conventional disk drive motor.

[Explanation of symbols]

 1A, 1B, 1C Disk drive motor 11 Hub for mounting recording disk 12 Rotor magnet 13 Rotating shaft 14 Yoke 15, 17 Ball bearing 15A, 17A Outer ring of ball bearing 15B, 17B Inner ring of ball bearing 16 Center hole of hub 17 Annular protrusion of hub 18 Disk mounting surface 19 Fixed shaft 20 Frame 21, 100 Bearing holding part 22 Shaft holding part 23 Bottom part of frame 25 Spacer 29 Flange part 30 Stator core 35 Coil 39 Connector 40 Pedestal 41 Stepped part of pedestal 44 Cylindrical part of pedestal 50 Adhesive 70 Balance Adjusting Piece 73, 74 Micro Gap Constituting Labyrinth Seal

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02K 21/22 H02K 21/22 M 29/00 29/00 Z F Term (Reference) 5H019 AA07 AA09 AA10 BB13 BB14 CC04 EE13 FF01 FF03 5H605 AA07 AA08 BB05 BB19 CC01 CC02 CC04 CC10 EB04 EB15 EB33 EB38 GG12 5H607 BB01 BB14 BB17 CC01 DD01 DD09 EE10 GG04 5H615 BB01 BB14 PP01 SS03 5H621 JK07 JK13K

Claims (8)

[Claims] 1. A rotating shaft extending downward from a hub for mounting a recording disk, a pair of ball bearings rotatably supporting the rotating shaft, and a cylindrical bearing holding the pair of ball bearings inside. A frame having a holding portion protruding from a bottom portion, a stator core held on an outer peripheral side of the bearing holding portion, a coil wound on the stator core, and an annular rotor mounted on the hub so as to face the stator core A disk drive motor having a magnet, wherein the frame is formed of a pressed product obtained by pressing a plate material so that the bearing holding portion protrudes in a cylindrical shape. . 2. The thickness of the bearing holding portion according to claim 1, wherein a thickness of the bearing holding portion is 0.8 to a thickness of a bottom portion of the frame.
A disk drive motor having a thickness of not more than twice and less than a maximum thickness of an outer ring of the ball bearing. 3. The bearing according to claim 1, wherein an annular pedestal having a step formed on an outer peripheral side is mounted on an outer peripheral surface of the bearing holding portion, and a stator core is held on the step of the pedestal. A disk drive motor characterized by the above-mentioned. 4. A frame having a cylindrical shaft holding portion protruding from a bottom, a fixed shaft held by the shaft holding portion, a pair of ball bearings held by the fixed shaft, and a pair of ball bearings. A recording disk mounting hub rotatably supported by the fixed shaft via the stator shaft, a stator core held on an outer peripheral side of the shaft holding portion, a coil wound around the stator core, and a face of the stator core. As described above, in the disk drive motor having the annular rotor magnet mounted on the hub, the frame is formed of a pressed product obtained by pressing a plate material so that the shaft holding portion protrudes in a cylindrical shape. A disk drive motor characterized in that: 5. The disk drive motor according to claim 4, wherein a step is formed on an outer peripheral side of the shaft holding portion, and the stator core is held on the step. 6. The shaft according to claim 4, wherein an annular pedestal having an annular step formed on an outer peripheral side is mounted on an outer peripheral surface of the shaft holding portion, and a stator core is held on the step of the pedestal. A disk drive motor characterized by the above-mentioned. 7. The cylindrical bearing holding portion according to claim 6, wherein the pedestal is provided between the ball bearing and an outer ring of a ball bearing disposed below the pair of ball bearings, and a cylindrical projection holding portion protruding downward from the hub. A disk drive motor, wherein a minute gap forming a labyrinth seal is formed between the disk drive and the lower end. 8. The disk drive motor according to claim 3, 6 or 7, wherein the pedestal is made of plastic.