JPH09275670A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor which is less influenced by vibration and noise generated at the time of operation. SOLUTION: This motor is provided with a shaft 1 which is rotatably supported, a hub stand 2 which is set and fastened to the shaft 1 and has an information media to be mounted on its upper face, a turn table 6 which is turned integrally with the hub stand 2, and a chucking magnet 4 which, being located on the turn table 6, chucks the information media by magnetism. Between the chucking magnet 4 and the turn table 6, an adhesive 5 for damping is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor that can be used for rotating a medium such as a hard disk or a floppy disk.

[0002]

2. Description of the Related Art For example, a motor shown in FIG. 4 is known as a motor used in a floppy disk drive device. In FIG. 4, a stepped protrusion 43a is provided at the center of the frame 43, and the protrusion 43a
A hole 43b is provided at the center of the. A cylindrical radial bearing 53 is press-fitted and fixed in the hole 43b. The radial bearing 53 has a flange 53a on the outer peripheral surface on the upper side, and the lower end surface of the flange 53a is in contact with the inner edge portion of the upper surface of the protruding portion 43a. A thrust ball bearing 40 is attached to the upper end surface of the protrusion 43a on the outer peripheral side of the flange 53a of the radial bearing 53.
The thrust ball bearing 40 has an upper plate 40a and a lower plate 40b that are rotatable relative to each other vertically around a ball. Of the upper plate 40a and the lower plate 40b, the lower plate 4
0b is in contact with the upper surface of the protruding portion 43a.

A substrate 42 is attached above the frame 43. The substrate 42 has a hole 42a in the center, and the thrust ball bearing 40 is located inside the hole 42a. A constant gap is formed between the lower surface of the substrate 42 and the flat surface portion on the outer peripheral side of the projecting portion 43 of the frame 43. Such a frame 43 and a substrate 4
2. The stator of the motor is composed of the air core coil 45 and other members.

In the center hole of the radial bearing 53, there is a rotating shaft 31.
Is inserted. The rotary shaft 31 is supported in the radial direction by a radial bearing 53. A rotor 33 is attached to the outer peripheral surface on the upper side of the rotating shaft 31. The rotor 33 includes members such as a hub base 32, a chucking magnet 34, a rotor case 36, and drive pins 38. Of these, the hub base 32 is fitted and fixed to the rotary shaft 31.

A concave step portion 32a is provided on the outer peripheral side of the lower portion of the hub base 32, and the upper plate 40a of the thrust ball bearing 40 is housed in the step portion 32a.
The upper surface of 0a is in contact with the ceiling surface in the step 32a.
Therefore, the hub base 32 includes the thrust ball bearing 4
0 is supported in the thrust direction and the rotary shaft 31
A rotor 33 including a hub base 32 and the like is rotatable with respect to a frame 43 that is a part of the stator.
In addition, the hub base 32 has a disk-like shape that expands to the outer peripheral side, and the upper end surface of this expanded portion is the disk mounting surface. A circular recess 32b centering on the rotary shaft 31 is provided on the disk mounting surface, and a chucking magnet 34 is mounted in the recess 32b so as to surround the rotary shaft 31.

Further, an inner concave portion 32c centering on the rotary shaft 31 is provided below the portion of the hub base 32 that spreads to the outer peripheral side, that is, on the frame 43 side, and further on the outer peripheral side of the stepped portion 32a. It is provided. A leaf spring 62 is provided in the recess 32c.
Is attached to the leaf spring 62.
8 is attached. The upper portion of the drive pin 38 penetrates the hub base 32 and is vertically recessed on the opposite side 32 b.
It protrudes to the side. The drive pin 38 can be sunk downward or returned to its original position by a leaf spring. Further, since the drive pin 38 is provided, the shape of the chucking magnet 34 is not a perfect circle shape but a horseshoe shape so that the drive pin 38 and the chucking magnet 34 do not interfere with each other.

A rotor case 36 is attached to the outer periphery of the hub base 32. The rotor case 36 has a peripheral wall on the outer peripheral side, and a ring-shaped drive magnet 63 is attached to a portion inside the peripheral wall.

The lower end surface of the driving magnet 63 is formed on the substrate 4
It faces the air-core coil 45 attached to the lower surface of 2 with a certain gap. Therefore, by controlling the energization of the air-core coil 45, the air-core coil 45 urges the drive magnet 63 in a certain direction, and as a result, the rotor including the hub base 32, the rotary shaft 31, etc. is rotationally driven.

A floppy disk is mounted on the hub base 32 of the motor configured as described above. The floppy disk is composed of a box-shaped case 60, a disk hub 50 exposed to the outside through a hole provided in the case 60, and a disk 51 mounted on the outer periphery of the disk hub 50 and housed inside the case 60. ing. The disk hub 50 has a square-shaped central hole 50a whose corners are arcuate in the center. When a floppy disk is mounted on the hub base 32, the tip of the rotary shaft 31 of the motor is inserted into the center hole 50a, and the center hole 50a
The rotating shaft 31 is engaged with the corner portion of a. Further, a drive hole for driving the disc is formed on the outer peripheral side of the center hole 50a of the disc hub, and the drive pin 38 is inserted into the drive hole.

When the rotor of the motor is rotationally driven with the floppy disk mounted on the hub base 32, the drive pin 38 contacts one side of the drive hole provided in the disk hub 50 of the floppy disk, and as a result, The floppy disk is driven to rotate about the rotary shaft 31 that is inserted into the center hole 50a and that is engaged with the corner portion of the center hole 50.

[0011]

When the motor is driven, a current flows through the air-core coil 45 to electromagnetically couple the air-core coil 45 and the rotor, and as a result, the rotor case 36 vibrates. However, since the motor for driving the floppy disk as described above has a low rotation speed, the vibration is small.

However, in recent years, the capacity of floppy disks has been increased and the access speed has been improved, and as a result, it has become necessary to rotationally drive the disks at a high speed. However, when the motor of the floppy disk drive having the above-described structure is rotated at high speed, vibration due to electromagnetic coupling becomes large and noise is increased.

Further, since the chucking magnet 34 has a horseshoe shape and the rotating shaft 31 which is the center of rotation is located at a position deviated from the center of the weight of the chucking magnet 34, the weight distribution of the rotor is unbalanced. It was in balance. Even if the weight distribution of the rotor is unbalanced, no problem occurs at low speed rotation. However, when a rotor whose weight is unbalanced is rotationally driven at high speed, there is a problem that vibration becomes large.

The present invention has been made in order to solve the above problems of the prior art, and an object of the present invention is to provide a motor in which the influence of vibration and noise during operation is eliminated.

[0015]

According to the first aspect of the present invention,
A rotatably supported shaft, a hub base fitted and fixed to the shaft to mount information media on the upper surface, a turntable that rotates integrally with the hub base, and a chucking magnet that is placed on the turntable and magnetically attracts the information media. And a vibration damping adhesive interposed between the chucking magnet and the turntable.

According to a second aspect of the present invention, the chucking magnet has an annular shape centered on the shaft, and the width in the radial direction is equal over the entire circumference.

According to a third aspect of the present invention, the chucking magnet is a rubber magnet in which magnetic powder is dispersed in a binder containing rubber, and the hardness thereof is 30 to 80 durometer.

The vibration generated by the electromagnetic coupling between the coil and the rotor is reduced by the damping adhesive interposed between the chucking magnet and the turntable.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a motor according to the present invention will be described below with reference to the drawings. Figure 1,
FIG. 2 shows a motor for rotationally driving a ZIP disk, which is a type of floppy disk. 1 and 2, a hole 13a is formed at the center of the substrate 13,
The lower end protruding portion 11c of the bearing holder 11 is inserted into the hole 13a.
Is fitted. The bearing holder 11 is the central cylindrical portion 1
1a, a flange 11b provided on the lower outer peripheral surface of the cylindrical portion 11a, and a protruding portion 11 protruding downward from the cylindrical portion 11a.
c, each part of the step part 11d formed on the inner peripheral surface of the cylindrical part 11a. Protrusion 11 of bearing holder 11
By inserting c into the hole 13a of the substrate 13 and bringing the lower surface of the flange 11b into contact with the upper surface of the substrate 13, the bearing holder 11 is arranged on the substrate 13 and the protrusion 11c is caulked. The bearing holder 11 is fixed to the substrate 13.

A stator core 9 is attached to the outer peripheral surface of the cylindrical portion 11a of the bearing holder 11. The stator core 9 is formed by laminating a plurality of magnetic plates of the same shape, has a plurality of salient poles on the outer circumference, and the coil 8 is wound around each salient pole. The lower surface of the stator core 9 on the inner peripheral side is in contact with the upper surface of the flange 11b of the bearing holder 11, and further, the base plate 13 and the flange 11b.
The tip end portion of the screw 12 penetrating through is screwed into the stator core 9 so that the substrate 13, the bearing holder 11,
The stator core 9 is integrated, and the bearing holder 11 and the stator core 9 are fixed on the substrate 13. A motor stator is configured from the above-described members such as the substrate 13, the bearing holder 11, and the stator core 9.

On the inner peripheral surface of the cylindrical portion 11a of the bearing holder 11, ball bearings 10 and 10 are attached vertically with a step 11d as a boundary. The outer races of the ball bearings 10 and 10 'are fitted and fixed to the inner peripheral surface of the cylindrical portion 11a. The shaft 1 is fitted and fixed to the inner rings of the ball bearings 10 and 10 '. The shaft 1 is rotatable with respect to the stator by the ball bearings 10 and 10 '.

A hub base 2 on which a medium such as a floppy disk is mounted is attached to the outer peripheral surface on the upper side of the shaft 1. A portion of the lower surface of the hub base 2 on the inner peripheral side is a protruding portion 2a protruding downward.
The lower end surface of a is in contact with the upper surface of the inner ring of the ball bearing 10.

A flat cup-shaped rotor case 6 is attached to the lower surface of the hub base 2 by caulking.
The rotor case 6 has a peripheral wall on the outer peripheral side and is configured to cover the stator core 9 from above. Also,
A drive magnet 7 is attached to the inner surface of the peripheral wall. The inner peripheral surface of the drive magnet 7 faces the tip surfaces of the salient poles of the stator core 9 with a certain gap. Therefore, by energizing the coil 8 wound around the salient poles of the stator core 9, the driving magnet 7 is biased in the circumferential direction, and the rotor case 6 is rotationally driven.

On the other hand, the outer edge portion of the upper surface of the hub base 2 is a disk mounting portion 2b which projects a little higher than the other portions, and the hub of a medium such as a floppy disk is mounted on the upper end surface of the disk mounting portion 2b. Will be installed. The hub base 2 and the rotor case 6 are the turntable 3
Is composed.

A chucking magnet 4 is attached on the upper surface of the turntable 3 including the rotor case 6 and on the outer peripheral side of the hub base 2. A damping adhesive 5 such as a double-sided tape is interposed between the chucking magnet 4 and the turntable 3, and the damping magnet 5 fixes the chucking magnet 4 on the turntable 6. There is. The chucking magnet 4 has an annular shape that is concentric with the shaft 1 and has the same radial width over the entire circumference, that is, the outer shape is a perfect circle and the inner shape is a perfect circle. ing. The chucking magnet 4 attracts the metal hub of the medium mounted on the hub base 2 and fixes the medium on the hub base 2.

The rotor of the motor is composed of the shaft 1, the hub base 2, the rotor case 6, the chucking magnet 7, the driving magnet 7 and the like.

According to the motor having the above structure, the chucking magnet 4 is arranged on the turntable 3 and on the outer peripheral side of the hub base 2, and the chucking magnet 4 and the turntable 6 are separated from each other. Since the vibration damping adhesive 5 is interposed between the vibration damping adhesive 5 and the motor, the turntable 3 and the coil 8 are electromagnetically coupled to each other when the motor is driven to rotate at high speed. It can be absorbed and reduced by the agent 5.
As the vibration-damping adhesive 5 to be used, a double-sided tape in which adhesive layers are formed on both surfaces of a fibrous base, or a highly viscous adhesive is more effective.

Further, the chucking magnet 4 has an annular shape which is concentric with the shaft 1 and has the same radial width over the entire circumference, that is, the outer shape is a perfect circle and the inner shape is a perfect circle. It is in a state. Therefore, the turntable 6 does not have an unbalanced weight distribution due to the chucking magnet 4 and can smoothly rotate even at high speed rotation, which also reduces vibration.

Further, the chucking magnet 4 is used.
Alternatively, a rubber magnet in which magnetic powder is dispersed in a binder containing rubber as a main component may be used. A chucking magnet using such a rubber magnet is
The hardness can be lowered (30 to 70 durometer). Such a chucking magnet 4 having low hardness
May be used in combination with the vibration damping adhesive 5,
Alternatively, the vibration may be reduced only by the chucking magnet 4 without using the vibration damping adhesive 5. Even the chucking magnet 4 alone can reduce vibration and noise to some extent.

FIG. 3 shows an example in which noise generated by vibration is compared between a motor having a structure for reducing vibration, that is, a motor having no vibration suppressing structure, and a motor having the vibration suppressing structure as described above. FIG. 3A shows an example of a motor having no vibration damping structure, and FIG. 3B shows the vibration damping structure as described above (damping adhesive 5, chucking magnet having a hardness of 50 durometer). The example of the motor which has is shown. As is clear from the figure, it is possible to increase
The level of noise due to vibration, which was about 8.4 dB-A, could be reduced to 25.4 dB-A as a whole.

The motor having the vibration damping structure according to the present invention is not limited to the motor for rotationally driving the ZIP disk. For example, the present invention can be applied as a motor for rotationally driving a floppy disk or a hard disk which has been generally used conventionally. In particular, if it is used for a flat motor, a great effect can be obtained.

[0032]

According to the present invention, since the vibration damping adhesive is interposed between the chucking magnet and the turntable, vibration and noise generated by electromagnetic coupling between the turntable and the coil are used for vibration damping adhesion. It becomes possible to reduce it with an agent. In addition, the chucking magnet has an annular shape centering on the shaft, and the width in the radial direction is made uniform over the entire circumference. Therefore, the imbalance in the weight distribution of the turntable is eliminated, and the turntable rotates. It is possible to reduce the generated vibration and noise. Further, since the chucking magnet is formed of a rubber magnet in which magnetic powder is dispersed in a binder containing rubber and the hardness thereof is set to 30 to 80 durometer, it is possible to reduce vibration and noise even by the chucking magnet. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a motor according to the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a diagram showing a noise level of a motor due to vibration.

FIG. 4 is a sectional view showing an example of a conventional motor.

[Explanation of symbols]

 1 Shaft 2 Hub stand 3 Turntable 4 Chucking magnet 5 Damping adhesive

Claims (3)

[Claims] 1. A shaft rotatably supported, a hub base fitted and fixed to the shaft and having an information medium mounted on an upper surface thereof, and a turntable which rotates integrally with the hub base.
A motor provided with a chucking magnet arranged on the turntable for magnetically attracting the information medium, wherein a damping adhesive is interposed between the chucking magnet and the turntable. The motor to drive. 2. The motor according to claim 1, wherein the chucking magnet has an annular shape centered on the shaft, and has the same radial width over the entire circumference. 3. The motor according to claim 1, wherein the chucking magnet comprises a rubber magnet in which magnetic powder is dispersed in a binder containing rubber, and the hardness thereof is 30 to 80 durometer.