JP2670685B2 - Disk drive motor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive motor such as a magnetic disk device used for recording and reproducing data on a magnetic disk.

[Prior Art and its Problems] Conventionally, there is, for example, one shown in FIG. 12 as an example of a motor for driving a magnetic disk (hereinafter, simply referred to as “motor”).

The motor 10 comprises an upright hollow shaft integrally projecting in the center of a circular mounting frame 17 made of aluminum die cast.
Hollow shaft 16 is press-fitted into 18. An armature 11 and a bearing 12 are press-fitted into the hollow shaft 16 and a bearing 13 is fitted in a gap. The upper end of a cup-shaped rotor (hereinafter simply referred to as “rotor”) 15 is press-fitted into the bearing 12, and the lower end of the rotor 15 is press-fitted into the other bearing 13 via an end plate 14. A permanent magnet 9 facing the armature 11 is provided on the inner surface of the rotor 15. Further, two disc springs 20 combined in series are inserted through the lower end of the hollow shaft 16.

The lead wire 23 of the armature 11 is pulled out to the outside through the lateral hole 21 formed in the hollow shaft 16 and the hollow portion 22 of the upright hollow shaft 12 because the bearing 13 at the lower end interferes with the lead wire 23.

 Another example is shown in FIG.

This motor 30 has a central shaft 32 integrated with a mounting frame 31.
The armature 33, the pair of bearings 34 and 35 are press-fitted into the armature 33, and the disc spring 36 is inserted thereinto. Bearings 34 and 35 have magnets 37 on the inner circumference.
Is provided with a rotor 38.

The lead wire 39 of the armature 33 is connected via the printed circuit board 40.
It is pulled out from the hole 41 of the mounting frame 31.

A plurality of magnetic disks G with which the magnetic heads H come in contact are mounted on the outer circumference of the rotor 38 so as to rotate integrally with the rotor 38.

However, in these motors, the outer peripheral surface of the side wall of the rotor has substantially the same size from one end to the other end, and therefore, the sizes of the rotor magnet and the stator housed inside the rotor are the same. Constrained to the outside diameter, especially small motors, for example 1.8 inches in diameter or
In a motor for driving a 2.5-inch disk, it is difficult to design and attach a rotor magnet and data, and from this aspect, improvement of the motor structure has been desired.

In addition, since the disk receiving portion for receiving the disk is located above the flange of the mounting frame, the height of the entire motor cannot be reduced, which sufficiently responds to recent miniaturization and thinning of the motor. I couldn't.

SUMMARY OF THE INVENTION An object of the present invention is to provide a disk drive motor capable of reducing the size and thickness of a motor while securing a sufficient space for a permanent magnet and a stator.

Another object of the present invention is to provide a disk drive motor capable of reliably supporting a disk.

[Means for Solving the Problems] In the present invention, a mounting frame, a shaft member provided on the mounting frame, a rotor rotatably mounted on the shaft member via a pair of bearings, and a rotor mounted on the rotor. In the disk drive motor including the permanent magnet and the stator arranged to face the permanent magnet, the mounting frame is
The rotor has a flat plate portion, a side wall portion extending from the flat plate portion, and a flange extending from the side wall portion, and the recess portion is defined by the flat plate portion and the side wall portion. A first side wall located above the inner peripheral portion of the disk receiving portion, and a second side wall located below the outer peripheral portion of the disk receiving portion, and both ends of the first side wall are The shaft is rotatably supported by the shaft member through the pair of bearings, and the discs and the spacers are alternately laminated on the receiving surface of the upper face of the disc receiving portion, and the plurality of discs are provided on the first side wall. The permanent magnet is mounted on the inner surface of the second side wall, the stator and the permanent magnet are housed in the recess of the mounting frame, and the outer diameter of the first side wall of the rotor is the outer diameter of the second side wall. It is set smaller than the diameter, and the disk receiving part is located above the stator and the permanent magnet. There, the receiving surface of the disc receiving portion is adjacent to the radial and axial directions on the upper surface of the flange of the mounting frame.

[Operation] In the drive motor of the present invention, most of the permanent magnets mounted on the second side wall of the rotor and the stator mounted on the mounting frame are the recesses defined by the flat plate portion and the side wall portion of the mounting frame. The height of the entire motor can be effectively reduced.

Further, since the first side wall on which the disc is mounted is provided on the upper side of the disc receiving portion, and the second side wall on which the permanent magnet is mounted is provided on the lower side of the disc receiving portion, the second side wall The outer diameter is not restricted by the inner diameter of the disc mounted on the rotor. Therefore, by setting the outer diameter of the first side wall to be smaller than the outer diameter of the second side wall, even if the motor mounts a relatively small disc, the permanent magnet and the stator are installed inside the second side wall. Sufficient space can be secured, and relatively large parts can be adopted among these parts.

Further, since both end portions of the first side wall of the rotor are supported by the shaft member via a pair of bearings, a portion where the disk is mounted, that is, a portion where a large load acts is reliably supported by the pair of bearings. Therefore, the vibration of the disc can be reduced.

[Embodiment] An embodiment of a motor according to the present invention will be described below with reference to the accompanying drawings.

1 and 2 show a first embodiment of the motor. In FIG. 1, the illustrated motor mounting frame includes a circular flat plate portion 53, a side wall portion 53a extending from an outer peripheral portion of the flat plate portion 53, and a flange 52 extending radially outward from an upper end portion of the side wall portion 53a. The side wall 53a and the flat plate portion 53 define a recess. The press-fitting part 54
The shaft member 56 is press-fitted into the press-fitting portion 54 so as to project inward (upward in FIG. 1).

The laminated iron core 58 of the stator 57 is press-fitted onto the outer periphery of the press-fitting portion 54. An armature coil 59 is wound around the laminated core 58, and a lead wire 60 of the armature coil 59 is drawn out from a hole 62 formed in the flat plate portion 53 via a printed circuit board 61. A rotor 65 is provided at a free end portion (upper end portion in FIG. 1) 56a of the shaft member 56 via a pair of bearings 63 and 64. Outer ring 63b, 6 of each of a pair of bearings 63, 64
Between 4b, a rigid steel spacer 66 is inserted (press-fitted) whose thickness error in the direction parallel to the shaft member 56 is controlled to 1 μm or less. The spacer 66 is C-shaped.

Dustproof seals 63d, 64d are provided on the pair of bearings 63, 64.

The rotor 65 is made of steel, and has a cup-like shape as a whole. The rotor 65 has a disc receiving portion 67 which is a horizontal portion, a first side wall 65a is provided above the disc receiving portion 67, and a second side wall 65a is provided below the disc receiving portion 67.
Is provided with a side wall 65b. As shown in FIG.
A plurality of magnetic disks G that come into contact with the magnetic heads H are mounted on the outer periphery of the side wall 65a with spacers B alternately interposed. Further, a permanent magnet 68 that faces the outer peripheral surface of the stator 57 via a gap C is attached to the inner surface 65d of the second side wall 65b.

In the embodiment, both ends of the first side wall 65a are rotatably supported by the shaft member 56 via a pair of bearings 63, 64, and most of the stator 57 and the permanent magnet 68, in the embodiment, substantially the same. The entire upper part is housed in the recess defined in the mounting frame 51. Therefore, this can effectively reduce the overall height of the motor. The disk receiving portion 67 covers the stator 57 and the permanent magnet 68 from above, and the receiving surface of the disk receiving portion 67 (the upper surface in FIG. 1, on which the lowest disk G is placed). Is close to the upper surface of the flange 52 of the mounting frame 51. Therefore, by reducing this gap, the overall height of the motor can be further reduced. Further, the first side wall 65a is provided on the upper side of the disc receiving portion 67, and the second side wall 65b is provided on the lower side thereof.
Is provided, the outer diameters of the first side wall 65a and the second side wall 65b can be set independently without being restricted by the size of the other side. Then, by making the outer diameter of the second side wall 65b larger than the outer diameter of the first side wall 65a, the rotor 65
Even if the disc G mounted on the
A sufficient space can be secured for the stator 57 and the permanent magnet 68 inside the side wall 65b, and the relatively large stator 57 and the permanent magnet 68 can be adopted even if the motor is downsized.

 Next, the order of assembling the above-mentioned motors will be described.

First, the laminated iron core 58 of the stator 57 is attached to the outer periphery 54a of the press-fitting portion 54.
Press-fit. Next, the shaft member 56 is press-fitted into the inner circumference 54b of the press-fitting portion 54. Bearings 63 and 64 in which spacers 66 have been inserted (press-fitted) between the outer races 63b and 64b in order to apply preload are previously press-fitted into the shaft member 56. Then, finally, the center hole 65c of the rotor 65 to which the permanent magnet 68 is attached is attached to the outer rings 63b and 64b by press fitting or an adhesive.

As a result, each component of the motor 50 can be sequentially incorporated without turning over the mounting frame 51.

Further, a pair of bearings 63, 64 are provided at the free end portion 56b of the shaft member,
Since the rotor 65 is cantilevered, the lead wire of the stator 57 is
60 can be pulled out easily.

Further, since the spacer 66 is inserted between the outer rings 63b and 64b, as shown in the partially enlarged view of FIG.
b and 64b are separated from each other and a preload is applied.

Preloading by the spacer method is easier than the known disc spring method shown in FIG.

As a result, the rotor 65 can be rotated while suppressing the shake of the disc receiving portion 67 to 0.005 mm or less.

 In addition to the above-mentioned assembling order, there is the following assembling order.

First, the shaft member 56 is press-fitted into the press-fitting portion 54 into which the stator 57 is press-fitted. Next, a pair of bearings 63, 64 with a spacer 66 interposed
The outer rings 63b and 64b are press-fitted or adhesively fixed to the center hole 65c of the rotor 65. And a pair of bearings integrated with the rotor 65
Inner rings 63a, 64a of 63, 64 are pressed into the free ends of the shaft member 56. Then, an external force (F in FIG. 2) parallel to the shaft member 56 is applied to the inner ring 63a of the upper bearing 63, and the inner ring 63a is pushed down slightly along the shaft member 56. In this state, the inner ring 63a is adhesively fixed to the shaft member 56 to remove the external force.

As a result, as shown in FIG. 2, preload is applied to the pair of bearings 63 and 64.

The preloading method is substantially the same as that of the embodiment described later.

In FIG. 3, in order to reduce the thickness of the motor 70, the laminated core 58 of the stator 57 is press-fitted into the annular protruding wall 72 formed on the flat plate 73 of the mounting frame 71 so as to surround the lower bearing 64. It is a thing.

The shaft member 96 of the motor 90 shown in FIG. 4 is the motor 50 of FIG.
Unlike the shaft member 56, the shaft member 96 is a stepped shaft having a large diameter portion 96a and a small diameter portion 96b, and the stepped portion 96c receives the inner ring 64a when the bearing 64 is press-fitted. It is a thing.

The motor 100 of FIG. 5 is different from the motor 50 of FIG. 1 so that the mounting positions of the pair of bearings 63 and 64 can be slightly changed so that the tip of the press-fitting portion 54 of the mounting frame 51 and one of the bearings 64 are arranged. The spacer 101 is interposed between the inner ring 64a and the lower surface of the inner ring 64a.

The motor 110 of FIG. 6 is different from the shaft member 56 of the motor 50 of FIG. 1 in that the shaft member 116 has the same diameter up to the root portion, and the shaft member 116 has a large diameter portion 116a and a small diameter portion 116b. The small diameter portion 116b is press-fitted into the press-fitting portion 114 having the same outer diameter as the outer diameter of the large diameter portion 116a.

7 is different from the shaft member 56 of the motor 50 in FIG. 1 in that a shaft member 126 is formed integrally with the flat plate portion 123 of the mounting frame 121 and is made to protrude. It is positioned by the spacer 119.

The motor 130 of FIG. 8 is a pair of bearings 6 of the motor 50 of FIG.
This is an example in which bearings 133, 134 different from 3, 64 are used.

As shown in FIG. 9 which is a partially enlarged view of the pair of bearings 133 and 134, the balls 133c and 134c are respectively inserted into the recesses 133a and 134a formed on the outer periphery of the shaft member 136.
Outer rings 133b and 134b are engaged with the outside of 134c.

The motor 130 is assembled by previously installing a pair of bearings 13 on the shaft member 136.
3,134 are assembled, the spacer 66 is inserted between the outer rings 133b, 134b for applying a preload, and the balls 133c are inserted into the recesses 133a and the outer ring 13b.
3b, the ball 134c is sandwiched between the recess 134a and the outer ring 134d. In this state, the shaft member 136 is pressed into the flat plate portion 53 to which the stator 57 is attached. And finally the outer ring
The rotor 65 is press-fitted into 133b and 134b.

Therefore, also in this motor 130, by applying a preload similarly to the motor 50 in FIG.

In the motor shown in FIGS. 10 and 11, the spacer 76 is omitted,
The structure is further simplified.

The motor 150 shown in FIG. 10 is the same as the motor 50 shown in FIG. 1 except that the spacer 66 is omitted. Therefore, the way of mounting the bearings 63 and 64 is different from that in FIG.

After the outer rings 63b and 64b of the bearings 63 and 64 are press-fitted or adhesively fixed to the center hole 65c of the rotor 65, the inner rings 63a and 64a are assembled into the shaft member 56. Then, as shown in FIG. 11, a preload F is applied to the inner ring 63a of the shaft member 63, and in this state, an adhesive is injected between the shaft member 56 and the inner ring 63a to be cured. After the adhesive has cured, the preload is removed. As a result, preload is applied to the bearings 63 and 64. This preloading method reduces the number of parts and saves space.

Also in this modified example, similarly to the above-described embodiment, the components of the motor can be sequentially incorporated without turning over the mounting frame 51, and the lead wires can be easily pulled out. Further, the swing of the rotor 65 can be reduced.

As is clearly shown in the drawings, the various modifications described above are the features of the present invention, namely, (1) the mounting frame is provided with a recess defined by the flat plate portion and the side wall portion extending from the flat plate portion. (2) The rotor is provided with a first side wall on which the disc is mounted on the upper side of the disc receiving portion and a second side wall on which the permanent magnet is mounted on the lower side of the disc receiving portion. (3) Most of the stator and the permanent magnets are housed in the recesses of the mounting frame, and the disk receiving portion covers the stator and the permanent magnets above. (4) Outside the first side wall of the rotor The diameter is set smaller than the outer diameter of the second side wall, and (5) the receiving surface of the disk receiving portion is close to the upper surface of the flange of the mounting frame. Same as the embodiment shown in FIGS. 1 and 2. Action effect of is achieved.

Although the above embodiments and modifications have been described as applied to a magnetic disk drive motor, the same structure can be applied to an optical disk device or a magneto-optical disk device.

EFFECTS OF THE INVENTION In the disk drive motor of the present invention, most of the permanent magnets mounted on the second side wall of the rotor and the stator mounted on the mounting frame are housed in the recesses of the mounting frame. The height of the entire motor can be effectively reduced.

Further, a first side wall is provided on the upper side of the disc receiving portion,
Since the second side wall is provided below the disk receiving portion, the outer diameter of the second side wall is not restricted by the inner diameter of the disk attached to the rotor. Therefore, by setting the outer diameter of the first side wall to be smaller than the outer diameter of the second side wall, even a small disk motor has a sufficient inner side of the second side wall for the permanent magnet and the stator. A space can be secured, and relatively large parts can be adopted for these parts.

Further, since both end portions of the first side wall of the rotor are supported by the shaft member via a pair of bearings, a portion where the disk is mounted, that is, a portion where a large load acts is reliably supported by the pair of bearings. Therefore, the vibration of the disc can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a motor according to the present invention. FIG. 2 is an enlarged sectional view of a bearing portion in the motor shown in FIG. FIG. 3 is a vertical cross-sectional view showing a modified example in which the mounting state of the stator is different from that in FIG. FIG. 4 is a longitudinal sectional view showing a modified example in which the shape of the press-fitting shaft is stepped. FIG. 5 is a vertical cross-sectional view showing a modified example in which a spacer is interposed between the mounting frame and the lower bearing. FIG. 6 is a vertical cross-sectional view showing a modified example in which the shaft members have the same diameter up to the root portion. FIG. 7 is a vertical cross-sectional view showing a modified example in which the shaft member is integrally molded with a flat plate and the outer diameters are the same up to the root portion. FIG. 8 is a longitudinal sectional view showing a modification of the structure in which the bearing is different from that in FIG. FIG. 9 is a vertical sectional view showing a bearing portion of the motor shown in FIG. FIG. 10 is a vertical cross-sectional view showing a modified example of a structure in which the bearing mounting structure is different from that in FIG. FIG. 11 is an enlarged sectional view of a bearing portion in the motor of FIG. 12 and 13 are vertical sectional views showing a conventional motor. G Magnetic disk (disk) 50,70,80,90,100,110,120,130,150 …… Motor 51,71,191,111,121,131 …… Mounting frame 56,96,116,126,136 …… Shaft member 57 …… Stator 63,64,133,134 …… Bearing 63a, 64a …… Inner ring 63b, 64b , 133b, 134b …… Outer ring 65, 85 …… Cup type rotor 65a …… First side wall 65b …… Second side wall 66 …… Spacer 67 …… Disk receiving part 68 …… Permanent magnet

Claims (1)

(57) [Claims] 1. A mounting frame, a shaft member provided on the mounting frame, a rotor rotatably mounted on the shaft member via a pair of bearings, and a permanent magnet mounted on the rotor. A disk drive motor including a stator arranged to face the permanent magnet, wherein the mounting frame has a flat plate portion, a side wall portion extending from the flat plate portion, and a flange extending from the side wall portion. A recess is defined by the flat plate portion and the side wall portion. The rotor has an annular disk receiving portion on which a disk is mounted, and a first portion located above an inner peripheral portion of the disk receiving portion. The side wall of the disc and the second portion located below the outer peripheral portion of the disc receiving portion.
Of the first side wall are rotatably supported by the shaft member via the pair of bearings, and the disc and the spacer are alternately provided on the receiving surface of the upper surface of the disc receiving portion. The plurality of disks are stacked and mounted on the first side wall,
The permanent magnet is mounted on the inner surface of the second side wall, the stator and the permanent magnet are housed in the recess of the mounting frame, and the outer diameter of the first side wall of the rotor is the second side. Is set smaller than the outer diameter of the side wall of the disk, the disk receiving portion covers above the stator and the permanent magnet, and the receiving surface of the disk receiving portion is arranged in the radial and axial directions on the upper surface of the flange of the mounting frame. A disk drive motor characterized by being close to.