JP2911760B2 - Disk drive motor - Google Patents

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.

[0002]

2. Description of the Related Art For example, a disk drive motor on which a 3.5-inch floppy disk or the like is mounted and driven to rotate is shown in FIG. In FIG. 5, the substrate 31 has a hole 31a at the center thereof.
A sintered oil-impregnated bearing 44 is inserted in a. The lower part of the sintered oil-impregnated bearing 44 is a protrusion 44 a, and the protrusion 44 a is inserted into the center hole 31 a of the substrate 31. A flange 44b is formed on the outer peripheral surface of the sintered oil-impregnated bearing 44, and the lower end surface of the flange 44b is in contact with the edge of the hole 31a at the center of the substrate. Therefore, the sintered oil-impregnated bearing 44 does not fall downward from the hole 31a, and
1 is mounted on. Further, a cylindrical holder portion 44a is formed above the sintered oil-impregnated bearing 44.

[0003] On the substrate 31, the flange 4 of the sintered oil-impregnated bearing 44
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.
Are formed with a plurality of salient poles. A coil 43 is wound around each salient pole on the outer periphery of the armature core 42.

One of the stacked magnetic plates constituting the armature core 42 has an extended portion 42 a extending to the sintered oil-impregnated bearing 44.
The inner edge portion 2a is bent and abuts on the upper end surface of the flange portion 44b of the sintered oil-impregnated bearing 44. A screw 45 is inserted from the lower end surface side of the substrate 31, and the tip 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 sintering oil-containing The sintered oil-impregnated bearing 44 is fixed on the substrate 31 by the flange 44b of the bearing 44 being pressed against the substrate 31 by the inner edge 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 a step surface formed inside the holder portion 44a.

The shaft 32 is inserted into the inner ring of the ball bearing 38. The shaft 32 is rotatable with respect to the substrate 31, the armature 33, and the like by a ball bearing 38. On the other hand, the lower end of the shaft 32 is inserted into the center hole of the sintered oil-impregnated bearing 44. The sintered oil-impregnated bearing 4 into which the lower end of the shaft 32 is inserted.
4, the inner diameter of the central hole 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 reduced. Has occurred. Therefore, when the shaft 32 is rotated by the ball bearing 38, the sintered oil-impregnated bearing 44
The lubricating oil oozes out of the clearance, and the outer peripheral surface of the lower end of the shaft 32 slides on the inner peripheral surface of the central hole of the sintered oil-containing 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 further to the outer peripheral side of the jetty 36a. The rotor case 34 is fixed to the hub base 36 by crushing the jetty 36a of the hub 36 to the outer peripheral side and caulking the inner peripheral edge of the rotor case 34.

A hub base 36 is provided above the rotor case 34.
An arm-shaped chucking lever 40 is attached to the outer peripheral side. The chucking lever 40 is mounted on the rotor case 34 so as to be swingable by an appropriate support member. Further, the other end of the chucking lever is integrally provided with a convex portion which is engaged with a hole of a hub of the floppy disk and rotationally drives the floppy disk. Further, on the rotor case 34,
A chucking magnet 41 that attracts the 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 the outer periphery, and a ring-shaped drive magnet 35 is mounted on 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 controlling the energization of the drive coil 43 wound around the salient poles of the armature core 42, the drive magnet 35 is biased, and the rotor 37 including the rotor case 34, the hub base 36, and the shaft 32 is rotationally driven. Is done.

When a floppy disk is mounted on the upper end surface of the hub base 36, the protrusion of the chucking lever 40 is engaged 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 formed. Is pushed by the convex part,
The floppy disk is driven to rotate.

[0011]

According to the disk drive motor constructed as described above, the shaft 32 and the sintered oil-impregnated bearing 44 are provided.
The shaft 32 was liable to cause runout due to the clearance generated between the shaft 32 and the shaft 32. Also, the hub 32 is attached to the shaft 32.
When press fitting 6 is required to have high accuracy, if the press fitting accuracy is not good, the disk mounting surface of the hub base 36 has run-out, thereby deteriorating the characteristics of the disk drive device.

Further, since the lower end of the hub base 36 is held by the upper end surface of the inner race of the ball bearing 38, the hub base 36 is affected by the backlash of the ball bearing 38 and the disk mounting of the hub base 36 is performed. The run-out occurred on the mounting surface.

Further, in order to reduce the thickness of the disk drive motor body, the ball bearing 38 may be reduced in size. However, the smaller the ball bearing 38, the higher the cost. It is difficult to obtain.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a thin and low-cost disk drive motor which does not have a runout of a disk mounting surface of a hub stand. And

[0015]

According to the first aspect of the present invention,
A substrate, a shaft fixed to the substrate, an armature fixed to the substrate, a drive magnet mounted on the rotor case facing the armature, and a hub fixed to the rotor case for 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 receiving a load in a thrust direction of the rotor and rotatably supporting the rotor. The inner peripheral surface of the inner hole and the outer peripheral surface of the shaft slide with each other,
The bearing means is sandwiched between the hub base and the substrate, and the bearing means is fitted to the outer periphery of the shaft, and the hub base is in contact with the bearing means.

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

The invention according to claim 3 is characterized in that 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.

[0018]

[Function] The disk drive motor is a fixed shaft type motor.
The hub base is supported rotatably in the radial direction by sliding between the outer peripheral surface of the shaft fixed to the substrate and the inner peripheral surface of the hub base, and further, a thrust ball bearing interposed between the hub base and the substrate. 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 substantially at the center 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, and a portion of the shaft 2 below the flange portion 2a is press-fitted or bonded and fixed to a hole of the substrate 1, and a lower end surface of the flange portion 2a It is in contact with the upper end surface.

On the substrate 1, an annular bearing means 8 is mounted on the outer periphery of the flange 2 a of the shaft 2. The bearing means 8 is a thrust ball bearing, and includes a lower plate 8a 'serving as a rail, a plurality of balls 8c disposed on the lower plate 8a', and a ball 8c disposed on the ball 8c.
The upper plate 8a driven in the circumferential direction with respect to the lower plate 8a '
And a retainer for holding the ball 8c. The grease 8b is provided between the ball 8c and the upper plate 8a and the lower plate 8a 'in order to smoothly rotate the ball 8c.
Is painted.

On the outer peripheral side of the bearing means 8 on the substrate 1,
An armature core 12 is mounted. 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 to prevent grease 8b from reaching the ball 8c of the bearing means 8 and infiltrating between the stacked magnetic plates. Armature core 12 covered with insulating resin
Has a plurality of salient poles on the outer periphery, and a coil 13 is wound around each salient pole. The armature 3 is constituted by the armature core 12 and the coil 13.

Above the flange portion 2a of the shaft 2, a disk-shaped hub base 6 is fitted. The hub base 6 is formed, for example, by sintering copper powder or iron powder, and has an innumerable number of pores as a whole. The hub 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 has become.

An eave portion 6b is formed on the outer periphery of the hub base 6, and a rotor case 4 is attached to a lower end surface of the eave portion 6b. Rotor case 4 is denoted by reference character A in FIG.
As shown in the figure, 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 the outer ridge 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 support member 20, and the chucking lever 14 can swing horizontally along the upper surface of the rotor case 4 by the support member 20. The other end of the chucking lever 14 is integrally provided with a concave portion 10 which engages with a hub hole formed in a center hub of the floppy disk. Also, on the upper surface of the rotor case 4,
On the outer peripheral side of the hub 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. An outer peripheral surface of the drive magnet 5 is attached to an 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 certain gap.

The hub 6, the rotor case 4, and the driving magnet 5 constitute a rotor 7. The rotor 7 is rotatable in the radial direction by sliding the inner hole 6 a of the hub 6 with respect to the shaft 2. Has become. That is, the shaft 2 plays a role of a radial bearing. Also, the rotor 7
Are supported in the thrust direction by the lower end surface of the ridge 6c of the hub 6 being in contact with the upper plate 8a of the bearing means 8. That is, the bearing means 8 plays a role of 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 center of magnetism of the drive magnet 5 in the axial direction is set to be higher than the center of magnetism 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 drive magnet 5 is urged downward in an attempt to make the magnetic center of the drive magnet 5 coincide with the magnetic center of the salient poles of the armature core. As a result, the rotor case 4 and the hub base 6 are also urged downward, resulting in a thrust load. When the jetty 6c of the hub 6 contacts the upper plate 8a of the bearing 8, the bearing 8 receives the thrust load, and the hub 6 is positioned in the axial direction. When the coil 13 wound around the salient poles of the armature core 12 is controlled to be energized, the drive magnet 5 is energized and the rotor 7 is
is driven to rotate together with a.

When a floppy disk is mounted on the hub 6, the rotation of the rotor case 4 causes the projection 10 of the chucking lever 14 to engage with the hub hole of the center hub of the floppy disk. The part 10 pushes the inner peripheral surface of the hub hole, and the floppy disk is driven to rotate in one direction.

According to the disk driving motor having the above structure, the shaft 2 is a fixed shaft which does not rotate, so that the shaft runout of the shaft can be completely eliminated. The bearing means 8 for supporting the rotor 7 in the thrust direction includes a ball 8
c has an upper plate 8a and a lower end of the ball 8c has a lower plate 8a '.
As a result, there is no backlash, and as a result, the runout of the disk mounting surface of the hub base 6 disposed on the bearing means 8 can be eliminated.

Since the shaft 2 has the function of a radial bearing, only one bearing means 8 which is a thrust ball bearing is required, and it is necessary to use a radial ball bearing or a sintered oil-impregnated bearing. There is no.
Therefore, the number of bearings used can be reduced as compared with the conventional example, and it is possible to contribute to the cost reduction of the disk drive motor. As the number of bearings decreases, the disk drive motor can be made thinner. Furthermore, since a type of bearing that is inserted into the shaft, such as a radial ball bearing, is not used, productivity can be improved and the cost can be reduced.

Further, since the surface of the armature core 12 is covered with the insulating resin, even if the grease 8b flows out of the ball 8c of the bearing means 8, it does not enter between the magnetic plates.

Furthermore, instead of covering the inner peripheral surface of the inner hole 2a with a coating agent, the hub base 6 made of a sintered material impregnates the entire porous body with a lubricating oil and uses the lubricating oil oozing from the porous body. The slidability between the inner hole 2a and the shaft 2 may be improved. But in this case,
In order to prevent the lubricant oil from oozing out on the disk mounting surface on the upper end surface of the hub base 6 and adversely affecting the disk to be mounted, the disk should be kept from oozing out onto the disk mounting surface. It is necessary to cover the mounting surface with a coating agent.

Although the disk drive motor is of the circumferentially opposed type, as shown in FIG. 4, the structure of the substrate 1, the shaft 2, the hub 6 and the bearing means 8 is kept as it is, and the hub 6 is swaged. A flat ring-shaped drive magnet 17 is attached 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 coils 18 are opposed to each other with a gap therebetween so that a surface-facing disk drive is performed. Motor may be configured. The configurations of the shaft 2, the hub 6 and the bearing means 8 are the same as those shown in FIGS.
Since it is the same as that of the circumferentially opposed type shown in (1), center runout and surface runout can be eliminated, and it is possible to contribute to a reduction in the physical size and cost.

[0034]

According to the first aspect of the present invention, the shaft is fixed, the inner peripheral surface of the inner hole of the hub base slides against the outer peripheral surface of the shaft, and a gap is formed between the hub base and the substrate. Because the bearing means is sandwiched, and the bearing means is fitted to the outer periphery of the shaft, and the hub stand comes into contact with the bearing means,
It is possible to eliminate the center runout of the shaft and the center runout of the disk mounting surface of the hub stand. In addition, the inner peripheral surface of the inner hole of the hub and the outer peripheral surface of the shaft are slid with each other, eliminating the need for conventional oil-impregnated sintered bearings, thereby reducing the thickness and cost. Becomes 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 stand, the rotation of the hub stand with respect to the shaft can be made smooth. It becomes possible.

According to the third aspect of the present invention, the hub base is
It is made of a sintered material, impregnated with lubricating oil, and the disk mounting surface is covered with a coating agent, so that the rotation of the hub with respect to the shaft is smooth and the lubricating oil is applied to the disk mounting surface. As a result, it is possible to eliminate adverse effects on the disk.

[Brief description of the 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 rear view showing a coupling portion between the hub stand 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]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Shaft 3 Armature 4 Rotor case 5 Drive magnet 6 Hub stand 6a Inner hole 7 Rotor 8 Bearing means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02K 29/00 H02K 5/16 H02K 21/22

Claims (3)

(57) [Claims] 1. A substrate, a shaft fixed to the substrate, an armature fixed to the substrate, a drive magnet mounted on a rotor case facing the armature, and fixed to the rotor case. A disk drive comprising: a hub base on which a disk is mounted; a rotor including the rotor case, the drive magnet and the hub base; and bearing means for receiving a load in the thrust direction of the rotor and rotatably supporting the rotor. A motor, wherein an inner peripheral surface of an inner hole of the hub stand and an outer peripheral surface of the shaft slide with each other, the bearing means is sandwiched between the hub stand and the substrate, and the shaft A disk drive motor, wherein the bearing means is fitted to the outer periphery of the disk drive, and the hub stand 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 a lubricating oil, and a disk mounting surface of the hub base is covered with a coating agent.
A disk drive motor according to any one of the preceding claims.