JP2599478Y2 - Magnetic 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 magnetic disk drive motor applied to, for example, a floppy disk drive.

[0002]

2. Description of the Related Art A magnetic disk drive motor for rotating a medium such as a floppy disk is known. FIG.
8 and 19 show examples of such a magnetic disk drive motor. In FIG. 18, a housing 34 has a cylindrical shape, and bearings 33 made of two upper and lower sintered materials are provided on the inner peripheral surface.
33 are attached. A flange 34a is formed on an outer peripheral surface of the housing 34, and a stator core 35 is attached to a lower end surface of the flange 34a. The stator core 35 has a plurality of salient poles on the outer periphery, and a coil 41 is wound around each salient pole. Such a stator set including the housing 34 and the stator core 35 is attached to the substrate 36. Substrate 36 and the core holder 38 between the lower end face of the stator core 35 is interposed, the substrate lower portion of the core holder 38 is 36
Is fitted into the hole 36a formed in the hole.

[0003] A shaft 32 is inserted through the inner peripheral side of the bearings 33 attached to the inner peripheral surface of the housing 34. The shaft 32 is supported in a radial direction by a bearing 33, and a lower end is supported in a thrust direction by a thrust bearing 37 attached to a substrate 36, and is rotatable.

A hub 31 on which media and the like are placed is fitted and fixed to the upper end of the shaft 32, and a cup-shaped rotor case 40 is caulked to the lower edge of the hub 31 by a method such as caulking. Has been fixed by. A driving magnet 42 is attached to the inner surface of the peripheral wall of the rotor case 40. The inner peripheral surface of the driving magnet 42 faces the salient poles of the stator core 35 with a certain gap. Therefore, by controlling the energization of the coil 41 wound around the salient pole,
The drive magnet 42 is energized, and the rotor 40 and the shaft 32
Is driven to rotate.

[0005]

In the conventional magnetic disk drive motor described above, the bearings 33, 33 are of a sintered oil-impregnated type, and the shaft 32 is inserted through the bearing 33. There is a slight gap between the bearing 32 and the bearing 33. Due to the gap, when the magnetic disk drive motor is driven to rotate, the tip of the shaft 32 oscillates and rattles.

When the magnetic disk drive motor rotates, the end of the shaft 32 shakes or rattles by applying a side pressure to the shaft 32 and pressing a part of the outer peripheral surface of the shaft 32 against the inner peripheral surface of the bearing 33. The problem is solved by rotating the drive. Axis 3
As described in Japanese Utility Model Application Laid-Open No. 2-88463, a side pressure magnet is arranged between specific salient poles of the stator core, and the side pressure magnet is used to apply a lateral pressure to the rotor case. There is a method of sucking a part.

In recent years, floppy disk drive devices and the like have been reduced in size or thickness, and magnetic disk drive motors have also tended to be reduced in size or thickness. However, when the size of the magnetic disk drive motor is reduced, sufficient space for mounting the side pressure magnet between the salient poles of the stator core 35 cannot be secured. Also, as the magnetic disk drive motor is made thinner, the side pressure magnets are also made thinner, which reduces the magnetic attraction force. Therefore, it is difficult to obtain a sufficient side pressure even if the side pressure magnets are used. turn into

Further, the side pressure magnet is fixed to the stator core 3.
Mounting between salient poles 5 causes an increase in assembly cost and material cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is a magnetic disk drive motor which is low in cost and can apply lateral pressure to a shaft regardless of the size. The purpose is to provide.

[0010]

Means for Solving the Problems The invention according to claim 1 is:
A hub base on which a disk is mounted and driven, a shaft fixed to the center of the hub base, a rotor case attached to one end of the shaft and having a driving magnet on the inner surface of the peripheral wall, and a shaft rotatable via a bearing. A substantially cylindrical housing for supporting the
In a magnetic disk drive motor having a substrate for supporting a stator core, one end of a bearing is in sliding contact with the hub base, and a cutout for inclining the shaft is formed on one end surface thereof.
It is characterized by having been done.

The invention according to claim 2 is characterized in that the housing is inclined with respect to the shaft.

According to a third aspect of the present invention, there is provided the magnetic disk drive motor according to the second aspect, wherein the housing is provided between the substrate or the housing of the magnetic disk drive motor and the chassis of the magnetic disk drive device in the direction opposite to the inclination of the shaft. Beside
It is characterized in that a spacer to be inclined is interposed .

The invention according to claim 4 is characterized in that the housing and the bearing are integrally formed of a sintered member.

According to a fifth aspect of the present invention, there is provided a magnetic disk drive motor according to the first aspect, wherein the substrate facing the drive magnet is provided with a bearing when the periphery thereof is viewed around the axis.
Protrudes to the drive magnet side on the same side as the cutout side
The projection is formed .

[0015]

[Function] A notch is formed on one end face of the bearing,
By supporting the shaft in the thrust direction by sliding the hub base against the end surface having the notch of the bearing, the shaft is tilted within the gap between the shaft and the bearing, and a side pressure is applied to the shaft.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic disk drive motor according to the present invention will be described below. In FIG. 1, a housing 4 has a cylindrical shape, and bearings 3 and 9 made of two upper and lower sintered materials are attached to the inner peripheral surface. Of the two upper and lower bearings 3, 9, the lower bearing 9 has a complete cylindrical shape, but the upper bearing 3 has a portion approximately half the center line of the upper end face as shown in FIG. Is cut out to form a notched portion 7.

In FIG. 1, a flange 4a is formed on the outer peripheral surface of the housing 4, and a stator core 5 is attached to a lower end surface of the flange 4a. Stator core 5
Is formed by laminating a plurality of core elements, a plurality of salient poles are formed on the outer periphery, and a coil 11 is wound around each salient pole. The stator set including the housing 4 and the stator core 5 is attached to an iron substrate 6. A spacer 8 is interposed between the substrate 6 and the lower end surface of the stator core 5.

The shaft 2 is inserted through the inner peripheral sides of the bearings 3 and 9 attached to the inner peripheral surface of the housing 4. The shaft 2 is supported in the radial direction by bearings 3 and 9, and the lower end of the shaft 2 is inserted into a hole 6 a formed in the center of the substrate 6. A hub 1 on which a medium such as a floppy disk is placed is attached to the upper end of the shaft 2. The lower end of the hub 1 is in contact with the upper end of the bearing 3. Therefore, the shaft 2 attached to the hub 1 is supported by the bearing 3 in the thrust direction. As shown in FIG. 2, the upper end of the bearing 3 has a cutout 7 formed by cutting out at least a half portion. For this reason, a portion of the hub base 1 located above the notch 7 is dropped toward the notch 7, and the shaft 2 is inclined toward the notch 7.

The hub base 1 has a cup-shaped rotor case 10.
It is fixed by caulking or the like. Since the shaft 2 is inclined toward the notch 7, the rotor case 10 attached to the hub 1 is also inclined in the same direction, that is, in the direction of arrow A in FIGS. A drive magnet 12 is attached to the inner surface of the peripheral wall of the rotor case 10, and the inner surface of the drive magnet 12 faces the salient pole of the stator core 5 with a gap. Therefore, by controlling the energization of the coil 11 wound around each salient pole, the drive magnet 12 is biased, and the rotor case 10 and the shaft 2 are driven to rotate.

As described above, the hub 1 fixed to the shaft 2
Is mounted on the shaft 2 by mounting the shaft 2 on the upper surface of the bearing 3, the shaft 2 is supported in the thrust direction by the bearing 3, and the notch 7 is formed in the upper part of the bearing 3. Since a part of the hub 1 falls into the notch 7, the shaft 2 is inclined toward the notch 7. When the shaft 2 is inclined toward the notch 7, the drive magnet 12 on the inclined side (the right side in FIG. 1) of the rotor case 10 comes closer to the iron substrate 6. Suction force increases. As the suction force increases, the rotor case 10 and the shaft 2 always maintain their inclined posture, and the suction force applies a lateral pressure to the shaft 2 to hold the shaft 2 at a specific location on the inner peripheral surface of the bearing 3. It can be rotated while turning on. With such a configuration, rotation of the hub stand without rattling or runout can be obtained, and there is no need to separately prepare a magnet for lateral pressure, so that costs can be reduced. Further, even if the size and thickness are reduced, a sufficient lateral pressure for inclining the shaft 2 can be obtained.

The shape of the bearing 3 used in the above embodiment is not limited to the shape shown in FIG. 2, but various shapes can be used. For example, as shown in FIG. 4 (a), more than half of the upper end of the bearing 3 may be cut out, or as shown in FIG. 4 (b), more than half of the upper end may be cut off obliquely. Good. Further, as shown in FIG. 4C, the entire upper end of the shaft 2 may be cut obliquely. In any of the examples, the shaft 2 tilts, and a side pressure is applied to the shaft 2 by the attraction force of the driving magnet 12 and the substrate 6.
It is possible to eliminate run-out and rattling when rotating.

Next, another embodiment will be described. FIG.
The housing 14 is cylindrical, and bearings 3 and 9 made of upper and lower two sintered materials are attached to the inner peripheral surface. Of the upper and lower two bearings 3, 9, the upper bearing 9 has a complete cylindrical shape. Further, the lower bearing 3 is formed with a notch 7 in a portion that is about half or more from the center line of the upper end surface, similarly to the above-described embodiment, and the posture is such that the notch 7 is on the lower side. Installed with.

A flange 14a is provided at the lower end of the housing 14.
Is formed, and an iron substrate 6 is attached to the upper end surface of the collar portion 14a. Housing 1 on top of substrate 6
A core holder 8 is attached to the outer periphery of 4, and a stator core 5 is attached to an upper end surface of the core holder 8 . The stator core 5 is formed by laminating a plurality of core bodies, and a plurality of salient poles are formed on the outer periphery. A coil 11 is wound around each salient pole on the outer periphery of the stator core 5.

A shaft 17 is inserted through the inner peripheral sides of the bearings 3 and 9 attached to the inner peripheral surface of the housing 14, and the shaft 17 is supported by the bearings 3 and 9 in the radial direction. A hub 16 is attached to the lower end of the shaft 17. The upper end surface of the boss portion of the hub base 16 is in contact with the lower end surface of the bearing 3. On the other hand, a cup-shaped rotor case 20 is fixed to the upper end of the shaft 17 with screws or the like.
A preload spring 15 is interposed between the rotor case 20 and the upper end surface of the bearing 9. The shaft 17 is urged upward by the preloading disc spring 15 with respect to the bearing 9 and the housing 14. A drive magnet 12 is mounted inside the peripheral wall of the rotor case 20, and an inner peripheral surface of the drive magnet 12 faces a salient pole of the stator core 5 with a gap. For this reason, by energizing the coil 11 wound around each salient pole of the stator core 5, the drive magnet 12 is energized and the rotor case 20, the shaft 1
7 and the hub base 16 are rotationally driven.

In the embodiment described above, the notch 7 is formed at the lower end of the lower bearing 3 of the upper and lower two bearings 9 and 3, and the shaft 17 is moved upward by the preload spring 15. Being energized. Therefore, a reaction is generated on the end surface of the boss portion of the hub base 16 which is in contact with the lower end surface of the bearing 3 in a direction opposite to the biasing direction of the shaft 17, that is, downward. On the other hand, the portion of the hub base 16 located below the notch 7 of the bearing 3 rises toward the end face of the notch 7 of the bearing 3. Along with this, the shaft 17 is inclined in the gap between the bearing 3 and the outer periphery of the shaft 17 is pressed against the bearing 9 and a specific portion of the inner periphery of the bearing 3 to apply a side pressure. When the magnetic disk drive motor is driven to rotate, the shaft 17 is driven to rotate while being pressed against the inner peripheral surfaces of the bearings 3 and 9.

The magnetic disk drive motor as described above is
As in the above-described embodiment, it is not necessary to separately prepare a magnet for lateral pressure, so that it is possible to keep the cost low and to eliminate the run-out and rattling during the rotational driving. In addition, since the shaft 17 can be inclined regardless of the size and thickness of the magnetic disk drive motor, a magnetic disk drive motor free from rattling and vibration can be obtained even if the size or thickness is reduced.

To incline the shaft 17 reliably, a bearing 3 having two upper and lower cutouts 7 may be attached to the inner periphery of the housing 14 as shown in FIG. In this case, of the two bearings 3, 3, the upper bearing 3 is mounted with the position of the notch 7 on the upper side, and the lower bearing 3 is mounted with the position of the notch 7 on the lower side. Notch 7, 7 is shaft 17
180 ° from the center. By doing so, the shaft 17 can be tilted and driven to rotate more reliably than in the above-described embodiments.

Each of the magnetic disk drive motors described above includes:
This is a configuration in which the parallelism of the hub base to the substrate falls within the range of the product standard even when the axis is inclined. However, when the axis is too tilted and exceeds the parallelism range of the product standard, it is necessary to correct the parallelism of the hub with respect to the substrate to be within the range of the product standard. The substrate 6 as shown in FIG.
In order to correct the parallelism of the hub 1 with respect to the substrate 6 beyond the range of the product specification in the magnetic disk drive motor having the rotor case 10 and the hub 1 on one side of FIG.
As shown in FIG. 3, a spacer 21 is interposed between the flange 4a on the side where the shaft 2 is inclined and the stator core 5, and the housing 4
What is necessary is just to incline itself in the direction opposite to the inclination of the shaft 2. By doing so, it is possible to correct the inclination of the axis 2 and to keep the parallelism within the range of the product standard.

Similarly, in a magnetic disk drive having a hub 16 on the opposite side of the rotor case 20 with respect to the substrate 6 as shown in FIG. 5, the substrate 6 of the hub 16 exceeds the product standard range. To correct the parallelism for
As shown in FIG. 8, a spacer 21 is interposed between the flange 14a on the side where the shaft 17 is inclined and the substrate 6 so that the housing 14 itself is inclined in a direction opposite to the inclination of the shaft 17. Good.

As another method of correcting the parallelism of the hub base, as shown in FIG. 9, a convex portion 6b is formed on the upper surface side of the substrate 6 on which the shaft 2 is inclined, and the tip of the convex portion 6b is formed. Housing 4
Alternatively, the housing 4 may be in contact with the lower end surface of the housing 2 and the housing 4 itself is inclined in a direction opposite to the inclination of the shaft 2. Such a configuration is also effective for a magnetic disk drive motor having a hub base on the side opposite to the rotor case with the substrate as the center as shown in FIG. That is, a projection 6b is formed on the lower end surface of the substrate 6 on the side where the shaft 17 is inclined, and the tip of the projection 6b is brought into contact with the flange 14a of the housing 14 so that the housing 14 can be tilted relative to the axis 2. Corrects the parallelism of the hub base by tilting in the opposite direction.

As another method of correcting the parallelism of the hub base, as shown in FIGS. 11 and 12, when the magnetic disk drive motor is mounted on the chassis 25 of the magnetic disk drive, the chassis 25 and the magnetic disk drive motor are mounted. Base
A method of interposing the spacer 22 between the plate 6 and the housing 4 is also conceivable.

Next, another embodiment of the present invention will be described. 13, the basic configuration of the magnetic disk drive is the same as FIG. 1, the iron of the substrate 6, when viewed around about the axis 2, and the notches 7 formed side of the bearing 3 On the same side and at a portion facing the end face of the drive magnet 12, a convex portion 2 facing the drive magnet 12 is provided.
3 are formed. By forming the convex portion 23, the distance between the upper end of the convex portion 23 and the end face of the drive magnet 12 is shorter than that of the other portions, so that the magnetic attractive force of the drive magnet 12 at the convex portion 23 is reduced. It becomes larger than the other parts, the shaft 2 is tilted with a strong force, and the lateral pressure applied to the shaft 2 can be increased. If the angle and the size of the notch 7 of the bearing 3 and the convex portion 23 facing each other around the shaft 2 are arbitrarily set, the magnitude of the lateral pressure can be arbitrarily changed.

As shown in FIG. 14, a part of the substrate 6 is cut away on the side 180 ° opposite to the notch 7 about the axis 2 and the projection surface of the drive magnet 12. You may make it. By doing this,
The distribution of the attractive force on the circumference of the drive magnet 12 becomes non-uniform, and the magnetic attractive force on the uncut side of the substrate 6 increases. For this reason, the lateral pressure applied to the shaft 2 can be increased. The angle at which the notch 7 of the bearing 3 and the cutout of the substrate 6 oppose each other about the shaft 2
The magnitude of the lateral pressure can be arbitrarily changed by arbitrarily setting the size of the removing portion .

In each of the embodiments described above, two bearings are mounted on the upper and lower sides in the housing. However, the present invention is not limited to this. For example, as shown in FIGS. 15 and 16, a magnetic disk drive motor may be configured using only one bearing 3 having a cutout 7. Good. Even in such a configuration, side pressure can be applied to the shaft and pressed against the bearing similarly to the magnetic disk drive motors of FIGS. 1 and 5 described above, so that rattling and runout can be largely eliminated. . As shown in FIG. 17, the bearing 19 also serving as a housing may be integrally formed by sintering, and the inner peripheral surface of the stator core 5 may be directly fitted and fixed to the outer periphery of the bearing 19. Since the housing is not used as a separate member, the cost can be reduced. In this case, since the outer diameter of the portion of the bearing 19 to which the stator core 5 is fitted and fixed is set to be the same as the inner diameter of the stator core 5, the outer diameter of the other portion of the bearing 19 is It is larger than the dimensions.

Note that, in the drawings, the inclination of the shaft and the hub base is drawn extremely large for easy understanding.
In fact, it's just a small tilt.

[0036]

According to the first aspect of the present invention, a hub base for mounting and driving a disk, a shaft fixed to the center of the hub base, and a driving magnet attached to one end of the shaft and provided on the inner surface of the peripheral wall. A magnetic disk drive motor including a rotor case having a rotor housing, a substantially cylindrical housing rotatably supporting a shaft via a bearing, and a substrate supporting a stator core, wherein one end of the bearing is in sliding contact with the hub base. , On the other hand
A notch for tilting the shaft is formed on the end face, so regardless of the size of the magnetic disk drive motor, a part of the hub stand falls into the notched portion of the bearing, causing the shaft to tilt. A lateral pressure can be applied to the shaft, and rotation without rattling or runout is possible.

According to the second aspect of the present invention, since the housing is inclined with respect to the shaft, the housing can be inclined in the direction opposite to the direction of inclination of the shaft to correct the parallelism of the hub with the substrate. it can.

According to the invention of claim 3 , according to claim 2,
In the magnetic disk drive motor described above, the housing is positioned between the substrate or the housing of the magnetic disk drive motor and the chassis of the magnetic disk drive in such a manner that the housing is opposite to the axis inclination.
Since the spacer for tilting is provided on the opposite side, the magnetic disk drive motor can be tilted on the opposite side to the tilt of the shaft, and the parallelism of the hub base to the substrate can be corrected.

According to the fourth aspect of the present invention, since the housing and the bearing are formed integrally with a sintered member, there is no need to prepare the housing as a separate member, and the cost can be reduced accordingly.

According to the invention of claim 5, according to claim 1,
Of the magnetic disk drive motor mounted on the board facing the drive magnet , looking around the axis
On the same side as the cutout side of the bearing, on the drive magnet side
Since the protruding protrusion is formed, the attraction force between the substrate and the driving magnet in this portion can be increased, and the lateral pressure applied to the shaft can be increased.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing an example of a bearing used in the magnetic disk drive motor.

FIG. 3 is a plan view of the magnetic disk drive motor.

FIG. 4 is a perspective view showing various examples of a bearing applicable to the magnetic disk drive motor of the above.

FIG. 5 is a sectional view showing another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 6 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 7 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 8 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 9 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 10 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 11 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 12 is a sectional view showing another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 13 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 14 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 15 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 16 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 17 is a sectional view showing still another embodiment of the magnetic disk drive motor according to the present invention.

FIG. 18 is a sectional view showing an example of a conventional magnetic disk drive motor.

FIG. 19 is a plan view showing the conventional example with a part cut away.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Hub stand 2 axis 3 Bearing 4 Housing 5 Stator core 6 Substrate 7 Notch 10 Rotor case 12 Drive magnet 21 Spacer 25 Chassis

Claims (5)

(57) [Scope of request for utility model registration] 1. A hub for mounting and driving a disk,
A shaft fixed to the center of the hub base, a rotor case attached to one end of the shaft and having a driving magnet on the inner surface of the peripheral wall, a substantially cylindrical housing rotatably supporting the shaft via a bearing, and a stator core One end of the bearing is in slidable contact with the hub base, and the shaft is inclined to one end surface of the magnetic disk drive motor.
A magnetic disk drive motor having a notch formed therein . 2. The magnetic disk drive motor according to claim 1, wherein the housing is inclined with respect to the shaft. 3. The housing is inclined between the substrate or the housing of the magnetic disk drive motor and the chassis of the magnetic disk drive in a direction opposite to the inclination of the shaft.
3. The magnetic disk drive motor according to claim 2, wherein a spacer is interposed . 4. The magnetic disk drive motor according to claim 1, wherein the housing and the bearing are integrally formed of a sintered member. 5. A substrate facing a drive magnet ,
Notch of the above bearing when looking around the shaft
On the same side as the part forming side
2. The magnetic disk drive motor according to claim 1, wherein the motor is formed.