JP2000262028A - Disc drive motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a disc drive motor in order to achieve the cost reduction by improving a hub and the structure of its surrounding parts. SOLUTION: A hub 11 of a rotary shaft type disc drive motor 1 is a stamping manufactured by press working a steel plate, etc. Therefore, the finish with the inside diameter, right circularity, etc., of a bearing retaining part 16 which have certain accuracy quality level or higher which cannot be obtained without secondary machining when a casting can be obtained. As a thick part does not exist when a stamping is employed as the hub 11, a ring piece 70 is fixed to the inside of the hub 11 and the ring piece 70 is utilized for adjusting the rotation balance of the hub 11 and form fine gaps 75 and 78 of which labyrinth seal is composed.

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 hub 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. In any of these types of motors, the frame and the hub are conventionally made of a casting such as aluminum die casting.

For example, a disk drive motor 1D shown in FIG. 5 is a shaft rotation type motor, and has 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
120 on which bearing 1 is formed and bearing holding portion 1
The rotor 111 is roughly composed of a stator core 130 held on the outer peripheral side of the coil 21 and a coil 135 wound around the stator core 130. An annular rotor magnet 112 is mounted on the hub 111 so as to face the stator core 130.
Is fixed through. An annular projection 125 is formed on the inner peripheral surface of the bearing holding portion 121, and upper and lower ball bearings 11 are formed on the annular projection 125.
By contacting the end faces of the outer races 115A and 117A of the ball bearings 117 and 117, the ball bearings 115 and 117 are positioned and the ball bearings 115 and 117 are positioned.
A preload is applied to.

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. Further, since the hub 111 is obtained by subjecting a cast product to secondary processing, it is easy to increase the thickness of a predetermined portion. Therefore, in the hub 111 shown in FIG. 5, the center portion 118 of the hub 111 is thickened to form the shaft holding portion 116 for holding one shaft end of the rotating shaft 113, and the thick portion around the shaft is formed. A hole 171 is formed from below and the hub 111
Adjustment of the rotation balance. Further, the hub 11
A minute gap 175 that forms a labyrinth seal is formed between the thick part 1 and the bearing holding part 121 formed on the frame 120.

[0005]

However, in spite of the strong demand for lowering the cost of the disk drive motor 1D, conventionally, the production of the hub 111 has conventionally required a casting process and a cutting process. And the like, there is a problem that the cost of the hub 111 itself is high and the cost of the motor cannot be reduced. In addition, there is a problem in that unnecessary material costs are incurred for cutting in the secondary processing. 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 the hub and its peripheral portion.

[0007]

In order to solve the above-mentioned problems, according to the present invention, a recording disk mounting hub having a shaft holding portion formed thereon, and one shaft end is held by the shaft holding portion. A frame formed with a rotating shaft, a pair of ball bearings having an inner ring fixed to the rotating shaft, and a cylindrical bearing holding portion having an outer ring of the pair of ball bearings fixed to an inner peripheral surface; A disk drive motor having a stator core held on an outer peripheral side of a holding portion, a coil wound around the stator core, and an annular rotor magnet mounted on the hub so as to face the stator core; Is constituted by a pressed product in which a plate material is subjected to press working so that the shaft holding portion protrudes downward in a cylindrical shape, and the rotary shaft is provided inside the hub. Wherein the heart-shaped in a ring piece is fixed.

In the present invention, the hub is a pressed product manufactured by subjecting a steel plate or the like to press working, and if such a pressed product is used, the hub is subjected to secondary processing unlike a cast product. Even if it is not necessary, the inner diameter and roundness of the shaft holding portion can be 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 hub can be manufactured at low cost. Also, material costs can be reduced. Therefore, the cost of the disk drive motor can be reduced. Also, when using a pressed product as the hub,
Since there is no thick portion, it is difficult to adjust the rotation balance of the hub and to form a minute gap that constitutes a labyrinth seal by using the thick portion. By using this ring piece, it is possible to adjust the rotational balance of the hub and to form a minute gap forming a labyrinth seal. In this case,
Because the hub is a pressed product, it is thin as a whole, so there is enough space to fix the ring pieces inside,
Further, even if such a ring piece is fixed to the hub, it does not prevent the motor from being downsized.

In the present invention, a lower end portion of the shaft holding portion contacts an upper end surface of an inner ring of a ball bearing disposed on an upper side of the pair of ball bearings, and applies a pressurizing force to the ball bearing. Is preferred.

[0010] In the present invention, the ring piece is provided with a minute clearance forming a labyrinth seal between the ring piece and the bearing holding portion, and further, with the outer ring of the ball bearing arranged above the pair of ball bearings. It is preferable that a minute gap forming a labyrinth seal is formed therebetween.

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 fixed shaft erecting from a frame, a pair of ball bearings having an inner ring fixed to the fixed shaft, and a cylindrical shape having an outer ring of the pair of ball bearings fixed to an inner peripheral surface. The bearing holding portion of the recording disk mounting hub protrudes downward from the upper surface portion, the stator core held on the frame side, the coil wound on the stator core, and the stator core facing the stator core. In a disk drive motor having an annular rotor magnet mounted on the hub, the hub is formed of a pressed product in which a plate material is pressed so that the bearing holding portion protrudes in a cylindrical shape, and A ring piece is fixed to the inside of the hub concentrically with the fixed shaft.

Also in the present invention, the hub is a pressed product manufactured by subjecting a steel plate or the like to press working, and if such a pressed product is used, unlike the cast product, the secondary working is performed. Even if it is not performed, the inner diameter of the bearing holding portion, the roundness, and the smoothness of the inner peripheral surface 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 hub can be manufactured at low cost. Also, material costs can be reduced. Therefore, the cost of the disk drive motor can be reduced. When a pressed product is used as the hub, since there is no thick portion, it is difficult to adjust the rotation balance of the hub using this thick portion, but as in the present invention, If the ring piece is fixed to the hub, such a problem can be solved. In this case, since the hub is a pressed product, it is thin as a whole, so that there is sufficient space for fixing the ring piece inside, and even if such a ring piece is fixed to the hub, the motor can be downsized. It does not hinder.

In the present invention, the thickness of the bearing holding portion is 0.8 times or less the thickness of the upper surface portion of the hub, and is smaller than the maximum thickness of the outer ring of the ball bearing. Is preferred. As described above, if the thickness of the bearing holding portion is reduced to some extent, even if the accuracy of the inner diameter and the roundness of the bearing holding portion is slightly lower,
When a ball bearing is mounted inside the ball bearing, even if the bearing holding portion side is distorted, the ball bearing is not distorted. Therefore, even if the cost of the motor is reduced by forming the hub by a pressed product, the ball bearing supports the hub in an appropriate posture, so that good motor characteristics can be maintained.

In the present invention, if a plastic piece is used as the ring piece, it is inexpensive and lightweight.

[0015]

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 1 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, a frame 20 in which a cylindrical bearing holding portion 21 for holding these ball bearings 15, 17 inside projects vertically from a bottom portion 23, and a stator core 30 held on the outer peripheral side of the bearing holding portion 21. It is roughly composed of a coil 35 wound around the stator core 30 and an annular rotor magnet 12 mounted on the hub 11 so as to face the stator core 30.

In this embodiment, the frame 20 is an aluminum die-cast product, and has a thick bearing holding portion 2.
1 has a shape projecting vertically from the bottom 23. 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 annular projection 251. Outer rings 15A and 17A of these ball bearings 15 and 17 are bearings. It is adhesively fixed to the inner peripheral surface of the holding part 21.

On the bottom portion 23 of the frame 20, near the bearing holding portion 21, a connector 39 for supplying power to the coil 35 wound around the stator core 30 is provided.
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 device or the like on which the motor is mounted by screws or the like.

Since the frame 20 is an aluminum die-cast product, the bearing holder 2 projecting up and down is used.
The center portion of the bearing 1 is considerably thick, and a step 255 for mounting the stator core 30 is formed by using the outer peripheral surface of the bearing holding portion 21. The stator core 30 arranged in this manner is fixed by the adhesive 50 applied from the upper surface to the outer peripheral surface of the bearing holding portion 21.

In this embodiment, the hub 11 is a pressed product manufactured by pressing a plate material such as a steel plate, and the cylindrical shaft holding portion 16 protrudes downward from the upper surface 150 by the pressing. Shape. The upper end portion (one shaft end) of the rotating shaft 13 is fitted and fixed to the shaft holding portion 16. Also, the rotating shaft 1
3, the inner rings 15B, 17 of the ball bearings 15, 17 disposed in the bearing holding portion 21
B is adhesively fixed. Further, a cap 55 is adhered and fixed to the outer end surface of the outer ring 17B of the ball bearing 17 at a position below the rotating shaft 13, so that the rust preventive used for the ball bearings 15 and 17 does not scatter. .

On the lower surface side of the hub 11, the lower end portion 17 of the shaft holding portion 16 protruding in a cylindrical shape is connected to the upper ball bearing 1.
5 is in contact with the upper end surface of the inner ring 15B, and a preload is applied to the ball bearing 15 so as to press down the inner ring 15B.

A plurality of steps are formed on the upper surface side of the hub 11, and a 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.

Further, inside the hub 11, the screw holes 1
A plastic ring piece 70 is fixed concentrically to the rotating shaft 13 on the back side of the step surface on which 10 is formed. A hole 71 of a predetermined size for adjusting the rotational balance of the hub 11 is formed at a predetermined position from the lower surface side of the ring piece 70.

The inner peripheral surface 72 of the ring piece 70 faces the outer peripheral surface of the bearing holding portion 21 of the frame 20 and forms a minute gap 75 forming a labyrinth seal with the outer peripheral surface of the bearing holding portion 21. are doing.

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 portion 119, 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 1 configured as described above, in the present embodiment, the hub 11 is a pressed product manufactured by pressing a steel plate or the like. For example, unlike a cast product, the inner diameter and roundness of the shaft holding portion 16 can be finished with a certain accuracy or more without performing secondary processing. Therefore, there is no need to perform a complicated casting process or secondary processing process,
The frame 20 can be manufactured at low cost. Also, material costs can be reduced. Therefore, the cost of the disk drive motor 1 can be reduced.

When a pressed product is used as the hub 11, there is no thick portion, and the thick portion is used to adjust the rotational balance of the hub 11 and to provide a small gap 75 forming a labyrinth seal. However, if the ring piece 70 is fixed to the inside of the hub 11 as in the present embodiment, the hub 1 can be formed using the ring piece 70.
This makes it possible to adjust the rotational balance and to form the minute gap 75 constituting the labyrinth seal. Therefore, even in the case of the hub 11 manufactured by press working, good rotation balance can be maintained, and scattering of lubricating oil and the like from the ball bearings 15 and 17 can be prevented. In this case, since the hub 11 is a pressed product and is thin as a whole, there is sufficient space for fixing the ring piece 70 inside, and even if such a ring piece 70 is fixed to the hub 11, the motor There is no hindrance to miniaturization.

Further, since the ring piece 70 is a molded plastic product, it is inexpensive and lightweight.

[Modification of First Embodiment] FIG. 2 is a half sectional view showing a disk drive motor according to a modification of the first embodiment of the present invention.

In FIG. 2, the disk drive motor 1A of this embodiment also has a rotating shaft 13 extending downward from a recording disk mounting hub 11, and a pair of ball bearings 15 rotatably supporting the rotating shaft 13. , 17, a frame 20 in which a cylindrical bearing holding portion 21 holding the ball bearings 15, 17 inside projects from a bottom portion 23, a stator core 30 held on the outer peripheral side of the bearing holding portion 21, It is roughly composed of a coil 35 wound around 30 and an annular rotor magnet 12 mounted on the hub 11 so as to face the stator core 30.

Also in the present embodiment, the hub 11 is a pressed product manufactured by pressing a sheet material such as a steel plate, as in the first embodiment.
The cylindrical shaft holder 16 has a shape protruding downward from 50. The rotating shaft 1 is
The upper end of 3 is fitted and fixed. Further, the bearing holding portion 2 of the frame 20 is
Inner ring 1 of ball bearings 15 and 17 arranged in 1
5B and 17B are adhesively fixed. Furthermore, the rotating shaft 1
3, the outer ring 1 of the ball bearing 17
A cap 55 is adhered and fixed to the outer end surface of 7B so that the rust preventive used for the ball bearings 15 and 17 does not scatter. Here, the ball bearing 17
The lower half protrudes below the lower surface of the frame 20, and a cap 55 having a side surface 550 is fitted to the protruding portion of the ball bearing 17. The adhesive 55 applied to the side surface 550, the outer ring 17A of the ball bearing 17, and the lower surface of the frame 20 is applied to the cap 55.
Therefore, the fixing strength of the cap 55 is high.

Also in this embodiment, on the lower surface side of the hub 11, the lower end portion 17 of the shaft holding portion 16 protruding in a cylindrical shape abuts against the upper end surface of the inner ring 15B of the upper ball bearing 15, so that the inner ring 15B is pressed down. Ball bearing 15
Is applied to the preload.

A plurality of step portions 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.

In the inside of the hub 11, the screw holes 1
A plastic ring piece 70 is fixed concentrically with respect to the rotating shaft 13 on the back side of the step surface on which 10 is formed. The ring piece 70 has a hole 71 for adjusting the rotational balance of the hub 11.

Here, the inner peripheral surface 72 of the ring piece 70 forms a minute gap 75 forming a labyrinth seal between the inner peripheral surface 72 of the ring piece 70 and the outer peripheral surface of the bearing holding portion 21 of the frame 20. Further, the ring piece 70 is provided with a protruding portion 77 which protrudes annularly inwardly toward the space between the ball bearing 15 and the hub 11, and the upper surface of the protruding portion 77 is bonded to the lower surface of the hub 11. I have. The lower surface of the projection 77 forms a minute gap 78 that forms a labyrinth seal with the upper end surface of the outer ring 17A of the ball bearing 15.

In this embodiment, the frame 20 is also 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. In this bearing holding portion 21, upper and lower ball bearings 15, 17 are ring-shaped spacers 2.
The outer races 15A and 17A of these ball bearings 15 and 17 are bonded and 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 also provided on the bottom 23 of the frame 20 near the bearing holder 21.
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 device or the like on which the motor is mounted by screws or the like.

In the present embodiment, since the frame 20 is a press-processed product, there is no extremely thin or thick portion as a whole. 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.

The other configuration is the same as that of the first embodiment, and the description is omitted.

In the disk driving motor 1A constructed as described above, the hub 11 is a pressed product manufactured by pressing a steel plate or the like, and requires a complicated casting process and a secondary processing process. No need to do.
Therefore, the frame 20 can be manufactured at low cost, and the material cost can be reduced. Therefore, the cost of the disk drive motor 1 can be reduced. When a pressed product is used as the hub 11, there is no thick portion. However, if the ring piece 70 is fixed inside the hub 11 as in the present embodiment, the ring piece 70 can be used. To adjust the rotation balance of the hub 11 and the small gap 7 forming the labyrinth seal.
5, 78 can be formed. In this case, since the hub 11 is a pressed product and is thin as a whole, there is sufficient space for fixing the ring piece 70 inside, and even if such a ring piece 70 is fixed to the hub 11, the motor There is no hindrance to miniaturization. Moreover, the ring piece 7
Since 0 is a plastic molded product, it is inexpensive and lightweight.

Further, in the present embodiment, the frame 20 is also a pressed product manufactured by subjecting a steel plate or the like to press working.
Unlike a cast product, the bearing can be finished with a certain degree or more in inner diameter, roundness, or smoothness of the inner peripheral surface of the bearing holding portion 21 without performing secondary processing. Therefore, there is no need to perform a complicated casting process or secondary processing process,
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.

Furthermore, 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. 3 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. 3, 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 the present embodiment, the frame 20 is formed of a pressed product in which a plate material such as a steel plate is pressed so that the shaft holding portion 22 protrudes in a cylindrical shape.

A connector 39 for supplying power to the coil 35 wound around the stator core 30 is mounted near the shaft holding portion 22 on the bottom portion 23 of the frame 20. 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 pressed 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 the present 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 the upper surface 150 thereof. The ball bearings 15 and 17 are vertically arranged in the bearing holding portion 100 with an annular spacer 25 interposed therebetween.
A and 17A are adhesively fixed to the inner peripheral surface of the bearing holding unit 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 precision in thickness dimensions and the like and is inexpensive because other parts are diverted. Also, the upper and lower ball bearings 15, 1
The outer rings 15A, 17A and the spacer 25 of No. 7 are all made 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, 1A of the upper and lower ball bearings 15, 17
The preload applied to the ball bearings 15 and 17 does not change because the 7A and the spacer 25 expand and contract similarly.

In the present embodiment, since the hub 11 is a pressed product, there is no extremely thin or thick portion as a whole, but the thickness t11 of the bearing holding portion 100 is 0.1 for a thickness t12 of 150.
8 times or less and the ball bearings 15, 1
7 is set to be thinner than the maximum thickness t3 of the outer races 15A and 17A.

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 has an upper half protruding from the upper end surface of the hub 11, and extends from the outer end surface of the outer ring 15 </ b> A of the ball bearing 15 to the outer peripheral surface at a position above the fixed shaft 19. A cap 56 having a side surface portion 560 is bonded and fixed to the ball bearing so that the rust preventive used for the ball bearings 15 and 17 is not scattered. Here, the adhesive 58
Is the side surface portion 560 of the cap 56, the ball bearing 15
Is applied over the outer peripheral surface of the outer ring 15A and the upper end surface of the hub 11, so that the adhesive strength of the cap 56 is high.

The hub 11 is a press-processed product. The upper surface of the hub 11 is formed with a plurality of steps, like the conventional hub, and the step surface on the outer peripheral side is the 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, a plastic ring piece 70 is adhered and fixed concentrically to the fixed shaft 19 by using a concave portion formed inside the hub 11, and a hole 71 is formed in the ring piece 70 from below. Thus, the rotation balance of the hub 11 is 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, the hub 11 is a pressed product manufactured by pressing a steel plate or the like. Unlike the product, the inner diameter and the roundness of the bearing holding portion 100 can be finished with a certain accuracy or more without performing the secondary processing. Therefore, there is no need to perform a complicated casting process or a secondary processing process, so that the hub 11 can be manufactured at low cost. Also, material costs can be reduced. Therefore, the cost of the disk drive motor 1 can be reduced.

When a pressed product is used as the hub 11, since there is no thick portion, it is difficult to adjust the rotational balance of the hub 11 by using the thick portion. If the ring piece 70 is fixed to the inside of the hub 11 as in the present embodiment, the rotation balance of the hub 11 can be adjusted using the ring piece 70. In this case, since the hub 11 is a pressed product and is thin as a whole, there is sufficient space for fixing the ring piece 70 inside, and even if such a ring piece 70 is fixed to the hub 11, the motor There is no hindrance to miniaturization.

Further, the thickness t of the bearing holding portion 100
11 is not more than 0.8 times the thickness t12 of the upper surface 150 of the hub 11 and has a ball bearing 15;
It is thinner than the maximum thickness t3 of the 17 outer rings 15A and 17A. As described above, since the thickness t11 of the bearing holding portion 100 is reduced to some extent, the bearing holding portion 100
Even if the accuracy of the inner diameter and roundness of the ball bearings are slightly lower, the outer ring of the ball bearings 15 and 17 may be distorted when the ball bearings 15 and 17 are mounted inside the bearings. 15A and 17A are not distorted. Therefore, even if the cost of the motor is reduced by forming the hub 11 by a pressed product, the ball bearings 15 and 17 can maintain good motor characteristics such as supporting the hub 11 in an appropriate posture. .

Furthermore, in the present embodiment, the frame 20
Is a pressed product manufactured by subjecting a steel plate or the like to press working. If such a pressed product is used, unlike the cast product, the shaft holding portion 22 can be formed without performing secondary processing. Finish with a certain degree of quality in terms of inner diameter, roundness, etc. 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 (the first embodiment), 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.

[Modification of Second Embodiment] FIG. 4 is a half sectional view showing a disk drive motor according to a modification of the second embodiment of the present invention. Since the basic structure of the disk drive motor of the present embodiment is almost the same as that of the second embodiment, the corresponding parts are denoted by the same reference numerals and the description thereof is omitted.

In FIG. 4, the disk driving motor 1C according to 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 this embodiment, the frame 20 and the hub 11 are formed of a pressed product in which a plate material such as a steel plate is pressed so that the shaft holding portion 22 and the bearing holding portion 100 protrude in a cylindrical shape. . Hub 1
The rotation balance of the hub 11 is adjusted using a plastic ring piece 70 fixed to the inside of the hub 1.

In the present 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.

[0071]

As described above, according to the present invention, in the disk drive motor of the rotating shaft type or the fixed shaft type, the hub is a pressed product manufactured by pressing a steel plate or the like. . Therefore, unlike the cast product, the inner diameter and the roundness of the shaft holding portion and the bearing holding portion can be finished with a certain accuracy or more without performing the secondary processing. Therefore, there is no need to perform a complicated casting step or a secondary processing step, so that the hub can be manufactured at low cost. Also,
Material costs can also be reduced. Therefore, the cost of the disk drive motor can be reduced. Furthermore, when a pressed product is used as the hub, since there is no thick portion, it is difficult to use this thick portion to adjust the rotation balance of the hub and to form a minute gap that forms a labyrinth seal. However, if the ring piece is fixed to the hub as in the present invention, it is possible to adjust the rotation balance of the hub and form a minute gap forming a labyrinth seal by using the ring piece. In this case, since the hub is a press-processed product, it is thin as a whole, so there is sufficient space for fixing the ring piece inside, and even if such a ring piece is fixed to the hub, the motor can be downsized. It does not hinder.

[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 an improved example of the first embodiment of the present invention.

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

FIG. 4 is a half sectional view of a disk drive motor according to an improved example of Embodiment 2 of the present invention.

FIG. 5 is a half sectional view of a conventional disk drive motor.

[Explanation of symbols]

1, 1A, 1B, 1C Disk drive motor 11 Hub for mounting recording disk 12 Rotor magnet 13 Rotary shaft 14 Yoke 15, 17 Ball bearing 15A, 17A Outer ring of ball bearing 15B, 17B Inner ring of ball bearing 16 Hub shaft Holder 17 Lower end of shaft holder of hub 18 Disk mounting surface 19 Fixed shaft 20 Frame 21 Bearing holder of frame 22 Frame holder 23 Frame bottom 25 Spacer 29 Flange 30 Stator core 35 Coil 39 Connector 40 Base 40 41 Stepped portion of pedestal 44 Cylindrical portion of pedestal 70 Ring piece 73, 74, 75, 78 Small gap forming labyrinth seal 100 Bearing holding portion of hub 150 Upper surface portion of hub

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H019 AA10 CC04 DD01 5H605 AA08 BB05 BB19 CC01 CC03 CC09 DD09 EB10 GG04 5H621 GA01 GA04 GB10 HH01 JK01 JK08 JK13

Claims (7)

[Claims] 1. A recording disk mounting hub having a shaft holding portion formed thereon, a rotating shaft having one shaft end held by the shaft holding portion, and a pair of balls having an inner ring fixed to the rotating shaft. A bearing, a frame having a cylindrical bearing holding portion in which an outer ring of the pair of ball bearings is fixed to an inner circumferential surface, a stator core held on an outer circumferential side of the bearing holding portion, and a winding around the stator core. Coil and
In a disk drive motor having an annular rotor magnet mounted on the hub so as to face the stator core, the hub is formed by pressing a plate material so that the shaft holding portion projects downward in a cylindrical shape. A disk drive motor comprising a pressed product, and a ring piece fixed to the inside of the hub concentrically with the rotating shaft. 2. The disk according to claim 1, wherein a lower end portion of the shaft holding portion is in contact with an upper end surface of an inner ring of a ball bearing disposed on an upper side of the pair of ball bearings. Drive motor. 3. The disk drive motor according to claim 1, wherein the ring piece has a minute gap forming a labyrinth seal between the ring piece and the bearing holding portion. 4. The method according to claim 1, wherein
The ring piece is one of the pair of ball bearings.
A disk drive motor, wherein a minute gap forming a labyrinth seal is formed between the ball bearing and an outer ring of a ball bearing disposed on an upper side. 5. A fixed shaft erecting from a frame, a pair of ball bearings having an inner ring fixed to the fixed shaft, and a cylindrical bearing holding portion having an outer ring of the pair of ball bearings fixed to an inner peripheral surface. A recording disk mounting hub protruding downward from an upper surface portion, a stator core held on the frame side, a coil wound around the stator core, and a hub mounted on the hub so as to face the stator core. A disk drive motor having an annular rotor magnet, wherein the hub is formed of a pressed product obtained by pressing a plate material such that the bearing holding portion protrudes in a cylindrical shape, and the hub is provided inside the hub. Wherein a ring piece is fixed concentrically with the fixed shaft. 6. The thickness of the bearing holding portion according to claim 5, wherein a thickness of the bearing holding portion is 0.8 times or less of a thickness of an upper surface portion of the hub, and is larger than a maximum thickness of an outer ring of the ball bearing. A disk drive motor characterized in that it is also thin. 7. The method according to claim 1, wherein
The disk drive motor according to claim 1, wherein the ring piece is made of plastic.