JPH0898489A - Disc drive motor - Google Patents

Abstract

PURPOSE: To obtain a thin disc drive motor in which the disc mounting surface of a hub base is protected against oscillation at low cost. CONSTITUTION: The disc drive motor comprises a substrate 1, a shaft 2 bonded thereto, an armature 3, a drive magnet 5 mounted on a rotor case 4, a hub base 6 for mounting a disc bonded to the rotor case 4, a rotor 7 including the rotor case 4, the drive magnet 5 and the hub base 6, and a bearing means 8 for supporting the rotor 7 rotatably while receiving a load in the thrust direction. An inner hole 6a of the hub base 6 slides, on the inner circumferential surface thereof, against the outer circumferential surface of the shaft 2. The bearing means 8 is held between the hub base 6 and the substrate 1 and fitted over the shaft 2 so that the bearing means 8 abuts against the hub base 6.

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 applicable to, for example, a 3.5-inch floppy disk drive device.

[0002]

2. Description of the Related Art For example, there is a disk drive motor having a structure shown in FIG. In FIG. 5, the substrate 31 has a hole 31a at the center thereof.
A sintered oil-impregnated bearing 44 is attached to a. A lower portion of the sintered oil-impregnated bearing 44 is a protrusion 44a, and the protrusion 44a is inserted into a hole 31a in the center of the substrate 31. A flange portion 44b is formed on the outer peripheral surface of the sintered oil-impregnated bearing 44, and the lower end surface of the flange portion 44b is in contact with the edge portion of the central hole 31a of the substrate. Therefore, the sintered oil-impregnated bearing 44 does not drop downward from the hole 31a to the substrate 3
It is mounted on 1. A cylindrical holder portion 44 a is formed on the sintered oil-impregnated bearing 44.

On the substrate 31, the collar portion 4 of the sintered oil-impregnated bearing 44 is provided.
An armature 33 is attached to the outer peripheral surface of 4b.
The armature 33 has an armature core 42 formed by laminating a plurality of magnetic plates.
A plurality of salient poles are formed on the outer periphery of the. A coil 43 is wound around each salient pole on the outer circumference of the armature core 42.

One of the laminated magnetic plates constituting the armature core 42 has an extending portion 42a extending to the sintered oil-impregnated bearing 44, and further, the extending portion 4
The inner edge portion of 2a is bent and abuts on the upper end surface of the collar portion 44b of the sintered oil-impregnated bearing 44. The screw 45 is inserted from the lower end surface side of the substrate 31, and the tip end of the screw 45 is screwed into the armature 33, whereby the armature 33 is fixed while being attracted to the substrate 31 side, and the sintered oil-impregnated oil is included. The sintered oil-impregnated bearing 44 is fixed on the substrate 31 by pressing the flange portion 44b of the bearing 44 toward the substrate 31 side by the inner edge portion of the extending portion 42a.

An outer ring of a ball bearing 38 is fitted and fixed to the inner peripheral surface of the holder portion 44a of the sintered oil-impregnated bearing 44. The lower end surface of the outer ring of the ball bearing 38 is in contact with the step surface formed inside the holder portion 44a.

The shaft 32 is attached to the inner ring of the ball bearing 38. The shaft 32 is rotatable with respect to the substrate 31, the armature 33, etc. by a ball bearing 38. On the other hand, the lower end of the shaft 32 is inserted into a central hole of the sintered oil-impregnated bearing 44. The sintered oil-impregnated bearing 4 in which the lower end of the shaft 32 is inserted
The inner diameter of the central hole of No. 4 and the outer diameter of the shaft 32 are substantially the same, but the inner diameter of the central hole of the sintered oil-impregnated bearing 44 is set to be slightly larger, and the clearance is Has occurred. Therefore, when the shaft 32 rotates by the ball bearing 38, the sintered oil-impregnated bearing 44
Lubricating oil oozes out into the clearance, and the outer peripheral surface of the lower end portion of the shaft 32 slides on the inner peripheral surface of the central hole of the sintered oil-impregnated bearing 44.

A hub base 36 is fitted and fixed to the outer peripheral surface of the shaft 32 above the ball bearing. The upper end surface of the hub base 36 is a disk mounting surface. Also,
A jetty 36a is formed on the lower end surface of the hub base 36. A rotor case 34 is attached to the lower end surface of the hub base 36 and on the outer peripheral side of the jetty 36a. The rotor case 34 is fixed to the hub base 36 by crushing the jetty 36 a of the hub 36 toward the outer peripheral side and caulking the inner peripheral edge of the rotor case 34.

A hub base 36 is provided on the rotor case 34.
An arm-shaped chucking lever 40 is attached on the outer peripheral side. The chucking lever 40 is mounted on the rotor case 34 so as to be swingable by an appropriate supporting member. Further, the other end of the chucking lever is integrally provided with a convex portion that engages with the hole of the hub of the floppy disk and drives the floppy disk to rotate. Furthermore, on the rotor case 34,
A chucking magnet 41 for attracting a floppy disk onto the hub base 36 is attached so as to surround the chucking lever 40 and the hub base 36.

The rotor case 34 has a peripheral wall on its outer periphery, and a ring-shaped drive magnet 35 is attached to the inner surface of the peripheral wall. The inner peripheral surface of the drive magnet 35 faces the salient poles of the armature core 42 with a certain gap. Therefore, by energizing the drive coil 43 wound around the salient poles of the armature core 42, the drive magnet 35 is urged, and the rotor 37 including the rotor case 34, the hub base 36, and the shaft 32 is rotationally driven. To be done.

Further, when a floppy disk is mounted on the upper end surface of the hub base 36, the protrusion of the chucking lever 40 engages with the hub hole of the floppy disk by the rotation of the rotor 37, and the inner peripheral surface of the hub hole. Is pushed by the convex part,
The floppy disk is driven to rotate.

[0011]

According to the disk drive motor having the above construction, the shaft 32 and the sintered oil-impregnated bearing 44 are provided.
Due to the clearance generated between the shaft 32 and the shaft 32, the shaft 32 is likely to cause runout. In addition, the hub base 3 is attached to the shaft 32.
High precision is required when press-fitting 6, and if the precision of press-fitting is not good, surface runout occurs on the disk mounting surface of the hub base 36, and the characteristics of the disk drive device are degraded.

Further, since the lower end portion of the hub base 36 is held by the upper end surface of the inner ring of the ball bearing 38, the hub base 36 is affected by rattling of the ball bearing 38, and the hub base 36 is mounted on a disk. There was surface wobbling on the placement surface.

Further, in order to make the disk drive motor main body thin, it is sufficient to downsize the ball bearing 38. However, the smaller the ball bearing 38 is, the higher the cost becomes, and thus the low cost disk drive motor is obtained. It's hard to get.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a thin and low-cost disk drive motor that does not cause surface runout of the disk mounting surface of the hub base. And

[0015]

According to the first aspect of the present invention,
Substrate, shaft fixed to the substrate, armature fixed to the substrate, drive magnet mounted to the rotor case facing the armature, hub fixed to the rotor case and mounting a disk A disk drive motor comprising: a base, a rotor case, a drive magnet, a rotor including a hub base, and bearing means for rotatably supporting the rotor by receiving a load in the thrust direction of the rotor, The inner peripheral surface of the inner hole and the outer peripheral surface of the shaft slide against each other,
The bearing means is sandwiched between the hub base and the base plate, and the bearing means is fitted to the outer periphery of the shaft so that the hub base contacts the bearing means.

The invention according to claim 2 is characterized in that the inner peripheral surface of the inner hole of the hub base is covered with a coating agent having good slidability.

According to a third aspect of the present invention, the hub base is made of a sintered material and is impregnated with lubricating oil, and the disk mounting surface of the hub base is covered with a coating agent.

[0018]

[Function] The disk drive motor is a fixed shaft type motor.
The hub base is rotatably supported in the radial direction by sliding the outer peripheral surface of the shaft fixed to the base plate and the inner peripheral surface of the hub base. Further, the hub base is a thrust ball bearing interposed between the hub base and the base plate. The load in the thrust direction applied to the hub base is supported by the bearing means such as.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a disk drive motor according to the present invention will be described below with reference to the drawings. Figure 1,
In FIG. 2, a hole is formed in a substantially central portion of the substrate 1, and a shaft 2 is attached to this hole. The shaft 2 has a flange portion 2a formed on the outer peripheral surface thereof. The portion of the shaft 2 below the flange portion 2a is press-fitted or adhesively fixed to the hole of the substrate 1, and the lower end surface of the flange portion 2a is formed on the substrate 1. It is in contact with the upper end surface.

On the substrate 1, an annular bearing means 8 is attached to the outer periphery of the shaft 2 from the flange portion 2a. The bearing means 8 is a thrust ball bearing, and includes a lower plate 8a 'that serves as a rail, a plurality of balls 8c arranged on the lower plate 8a', and a ball 8c arranged on the balls 8c.
The upper plate 8a which is driven in the circumferential direction with respect to the lower plate 8a 'by
And a retainer that holds the ball 8c. In addition, between the ball 8c and the upper plate 8a and the lower plate 8a ', in order to smooth the rotation of the ball 8c, grease 8b is provided.
Is painted.

On the outer peripheral side of the bearing means 8 on the substrate 1,
The armature core 12 is attached. Armature core 12
Is formed by laminating a plurality of magnetic plates. The surface of the armature core 12 is covered with an insulating resin so that the grease 8b does not extend from the ball 8c portion of the bearing means 8 to the space between the laminated magnetic plates. Armature core 12 covered with insulating resin
Has a plurality of salient poles on its outer circumference, and a coil 13 is wound around each salient pole. The armature 3 is configured by the armature core 12 and the coil 13.

A disc-shaped hub base 6 is fitted above the flange portion 2a of the shaft 2. The hub base 6 is formed, for example, by sintering copper powder or iron powder, and has an infinite number of pores throughout. The hub base 6 is
The inner peripheral surface has an inner hole 6a covered with a coating agent, the shaft 2 is inserted into the inner hole 6a, and the inner peripheral surface of the inner hole 6a slides with respect to the outer peripheral surface of the shaft 2. It is like this.

An eaves portion 6b is formed on the outer peripheral portion of the hub base 6, and a rotor case 4 is attached to the lower end surface of the eaves portion 6b. In the rotor case 4, the upper end surface of the inner peripheral edge portion is in contact with the lower end surface of the eaves portion 6b, the reference numeral A in FIG.
As shown in (4), a part of the jetty 6c formed on the lower surface side of the hub base 6 is fixed to the hub base 6 by crushing and crimping a part of the jetty 6c to the outer peripheral side, that is, the rotor case 4 side.

In FIGS. 1 and 2, an arm-shaped chucking lever 14 is attached to the upper part of the rotor case 4 on the outer peripheral side of the hub base 6. Chucking lever 1
One end of 4 is mounted on the rotor case 4 by an appropriate supporting member 20, and the supporting member 20 allows the chucking lever 14 to swing horizontally along the upper surface of the rotor case 4. In addition, a recess 10 that engages with a hub hole formed in the center hub of the floppy disk is integrally provided at the other end of the chucking lever 14. Also, on the upper surface of the rotor case 4,
On the outer peripheral side of the hub base 6 and the chucking lever 14,
A chucking magnet 11 for attracting the center hub of the floppy disk is attached.

The rotor case 4 is cup-shaped and has a peripheral wall on the outer periphery, and the outer peripheral surface of the drive magnet 5 is attached to the inner peripheral surface of the peripheral wall. The inner peripheral surface of the drive magnet 5 faces the salient poles of the armature core 12 with a constant gap.

The hub base 6, the rotor case 4, and the drive magnet 5 constitute a rotor 7. The rotor 7 is rotatable in the radial direction by sliding the inner hole 6a of the hub base 6 with respect to the shaft 2. Has become. That is, the shaft 2 serves as a radial bearing. Also, the rotor 7
Is supported in the thrust direction by the lower end surface of the jetty 6c of the hub base 6 contacting the upper plate 8a of the bearing means 8. That is, the bearing means 8 serves as a thrust bearing. Therefore, the rotor 7 is rotatable with respect to the substrate 1 and the armature 3 by the shaft 2 and the bearing means 8.

The magnetic center of the drive magnet 5 in the axial direction is set to be located above the magnetic center of the armature core 12 in the axial direction. By arranging the drive magnet 5 and the stator core 12 in such a positional relationship, the magnetic center of the drive magnet 5 tends to coincide with the magnetic center of the salient pole of the armature core, and the drive magnet 5 is urged downward. As a result, the rotor case 4 and the hub base 6 are also urged downward to generate a thrust load. When the jetty 6c of the hub base 6 contacts the upper plate 8a of the bearing means 8, the bearing means 8 receives the thrust load, and the hub base 6 is positioned in the axial direction. When the coil 13 wound around the salient poles of the armature core 12 is energized, the drive magnet 5 is energized and the rotor 7 is forced to the upper plate 8 of the bearing means 8.
It is driven to rotate together with a.

When the floppy disk is mounted on the hub base 6, the projection 10 of the chucking lever 14 is engaged with the hub hole of the center hub of the floppy disk by the rotation of the rotor case 4, and the projection is formed. The portion 10 pushes the inner peripheral surface of the hub hole to rotate the floppy disk in one direction.

According to the disk drive motor having the above structure, since the shaft 2 is the fixed shaft which does not rotate, the runout of the shaft can be completely eliminated. Further, the bearing means 8 for supporting the rotor 7 in the thrust direction is the ball 8
The upper end of c is the upper plate 8a and the lower end of the ball 8c is the lower plate 8a '.
Since it is always in contact with, there is no rattling, and as a result, surface runout of the disk mounting surface of the hub base 6 arranged on the bearing means 8 can be eliminated.

Further, since the shaft 2 has the function of a radial bearing, the bearing need only be one of the bearing means 8 which is a thrust ball bearing, and it is necessary to use a radial ball bearing or a sintered oil-impregnated bearing in addition to this. There is no.
Therefore, the number of bearings used can be reduced as compared with the conventional example, and the cost of the disk drive motor can be reduced. Since the number of bearings is reduced, the disk drive motor can be made thinner. Furthermore, since a bearing that is inserted into the shaft, such as a radial ball bearing, is not used, this also contributes to productivity improvement and cost reduction.

Furthermore, since the surface of the armature core 12 is covered with the insulating resin, even if the grease 8b flows out from the ball 8c portion of the bearing means 8, it will not penetrate between the magnetic plates.

Further, in the hub base 6 made of a sintered material, instead of covering the inner peripheral surface of the inner hole 2a with a coating agent, the entire porous material is impregnated with lubricating oil, and the lubricating oil oozing from the porous material is used. The slidability between the inner hole 2a and the shaft 2 may be improved. But in this case
In order to prevent the lubricating oil from oozing out on the disk mounting surface on the upper end surface of the hub base 6 and adversely affecting the mounted disk, the lubricating oil should not leak to the disk mounting surface. It is necessary to cover the mounting surface with a coating agent.

Although the disk drive motor was of the circumferentially opposed type, as shown in FIG. 4, the structure of the substrate 1, the shaft 2, the hub base 6, and the bearing means 8 was left unchanged, and the hub base 6 was swaged. Attach a flat ring-shaped drive magnet 17 to the ceiling surface of the rotor case 15 fixed by
In addition, a plurality of air-core coils 18 are arranged on the substrate 1 on the outer peripheral side of the bearing means 8 in the circumferential direction, and the drive magnet 17 and the air-core coil 18 are opposed to each other with a gap therebetween to drive a surface-opposed disk. The motor for motor may be configured. The configurations of the shaft 2, the hub base 6, and the bearing means 8 are the same as those shown in FIGS.
Since it is the same as the circumferentially opposed type shown in FIG. 1, core runout, surface runout, etc. can be eliminated, and it is possible to contribute to a thinner physique and lower cost.

[0034]

According to the first aspect of the invention, the shaft is fixed, and the inner peripheral surface of the inner hole of the hub base and the outer peripheral surface of the shaft slide against each other, so that the hub base and the base plate are sandwiched. Since the bearing means is sandwiched and the bearing means is fitted to the outer periphery of the shaft so that the hub base contacts the bearing means,
It is possible to eliminate the runout of the shaft and the runout of the disk mounting surface of the hub base. Also, by making the inner peripheral surface of the inner hole of the hub base and the outer peripheral surface of the shaft slide on each other, it is possible to eliminate the previously required sintered oil-impregnated bearing, which results in thinner and lower cost. Is possible.

According to the second aspect of the present invention, since the coating agent having good slidability is attached to the inner peripheral surface of the inner hole of the hub base, the rotation of the hub base with respect to the shaft can be made smooth. It will be possible.

According to the invention of claim 3, the hub base is
It is made of sintered material and is impregnated with lubricating oil, and since the disk mounting surface is covered with a coating agent, it makes rotation of the hub base relative to the shaft smooth, and lubricating oil is applied to the disk mounting surface. It is possible to eliminate the adverse effect on the disk.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a disk drive motor according to the present invention.

FIG. 2 is an enlarged sectional view of the same.

FIG. 3 is an enlarged back view showing a connecting portion between the hub base and the rotor case in the embodiment.

FIG. 4 is a sectional view showing another embodiment of the disk drive motor according to the present invention.

FIG. 5 is a sectional view showing an example of a conventional disk drive motor.

[Explanation of symbols]

 1 substrate 2 shaft 3 armature 4 rotor case 5 drive magnet 6 hub base 6a inner hole 7 rotor 8 bearing means

Claims (3)

[Claims] 1. A substrate, a shaft fixed to the substrate, an armature fixed to the substrate, a drive magnet mounted in a rotor case facing the armature, and fixed to the rotor case. For driving a disk, which includes a hub table on which a disk is mounted, a rotor including the rotor case, a drive magnet, and a hub table, and bearing means for rotatably supporting the rotor under a load in the thrust direction of the rotor. In the motor, the inner peripheral surface of the inner hole of the hub base and the outer peripheral surface of the shaft slide on each other, the bearing means is sandwiched between the hub base and the substrate, and the shaft A disk drive motor characterized in that the bearing means is fitted around the outer periphery of the hub base, and the hub base is in contact with the bearing means. 2. The disk drive motor according to claim 1, wherein the inner peripheral surface of the inner hole of the hub base is covered with a coating agent having good slidability. 3. The hub base is made of a sintered material, is impregnated with lubricating oil, and the disk mounting surface of the hub base is covered with a coating agent.
The disk drive motor described.