JPH09139017A - Floppy disk driving motor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the assembling cost of a rotor and also to prevent the index magnet from falling. SOLUTION: This motor is equipped with a center shaft 1, a rotor case 2 to be rotated integrally with the center shaft 1, a driving magnet 3 fixed to the rotor case 2, a driving pin 4 installed on the rotor case 2 so as to be engaged with an eccentric hole of a medium hub, a hub base 5a for mounting the medium hub, a chucking magnet 5b for magnetically attracting the medium hub and the index magnet 5c provided on the rotor case 2. In this case, the hub base 5a and the chucking magnet 5b are integrally molded out of a resin magnet, and also the index magnet 5c protruded from the lower surface of the rotor case 2 through a hole bored in the rotor case 2 is integrally molded out of the resin magnet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floppy disk drive motor applicable to, for example, a floppy disk drive device and a manufacturing method thereof.

[0002]

2. Description of the Related Art For example, as shown in FIG. 4, there is known a floppy disk drive motor applied to a floppy disk drive device or the like. In FIG. 4, the bearing holder 37 is fixed to the hole 38a formed in the center of the substrate 38 by caulking or the like. Bearing holder 3
7 has a concave shape, and a hole 37c is formed in the center of the bottom plate 37a in the concave portion. The bearing 36 is fitted and fixed inside the concave portion of the bearing holder 37. The bearing 36 is a ball bearing, and the center hole of its inner ring communicates with the hole 37c of the bearing holder 37.

A stator core 39 is attached to the outer peripheral surface of the bearing holder 37. The stator core 39 is configured by laminating a plurality of magnetic plates, has a plurality of salient poles radially on the outer circumference, and a coil 40 is wound around the arm portion of each salient pole.

On the other hand, the center shaft 31 is fitted to the inner ring of the bearing 36. The center shaft 31 is rotatably supported by a bearing 36 with respect to a stator including a bearing holder 37, a stator core 39, and a substrate 38. A hub base 42, on which a media hub such as a floppy disk (not shown) is mounted, is attached to the outer peripheral surface of the central shaft 31 above the bearing 36. A cup-shaped rotor case 32 is fixed to the outer edge portion of the end surface of the hub base 42 on the bearing 36 side by caulking or the like. A support member (not shown) is attached to the surface of the rotor case 32 on the side of the stator core 39, and one end of a swing arm (not shown) is attached to this support member. The support member allows the swing arm to swing in a plane parallel to the plane of the hub base 42. A drive pin 34 is attached to the other end of the swing arm. The drive pin 34 is
It projects upward from a hole 32a provided in the upper end surface of the rotor case 32. Further, the drive pin 34 has a groove on the outer peripheral surface thereof, and this groove has a form in which a part of the rotor case 32 is bitten. Since the hole 32a is larger than the drive pin 34, the drive pin 34 can be moved within the hole 32a by swinging a swing arm (not shown).

A chucking magnet 35 is attached to the upper surface of the rotor case 32 so as to surround the drive pin 34 protruding from the upper surface of the rotor case 32.
In addition, the lower surface of the rotor case 32, that is, the stator core 3
Index magnet 43 for position detection on the 9 side
Is attached.

A drive magnet 33 is attached to the inner surface of the peripheral wall of the rotor case 32. Drive magnet 3
The inner peripheral surface of 3 faces the salient poles of the stator core 39 with a constant gap. Therefore, when the coil 40 wound around the arm of the salient pole is energized, the drive magnet 33 is urged, and the hub base 42 on which the media shaft such as the central shaft 31 and the floppy disk is mounted is rotationally driven. .

Further, a flange is formed on the peripheral wall of the rotor case 41 having the drive magnet 33 mounted on the inner peripheral surface thereof, and the frequency generating magnet 41 is mounted on the lower end surface of the flange. Also, of the substrate 38,
A pattern for frequency power generation is formed at a position facing the magnet 41 for frequency power generation with a gap.

[0008]

In the floppy disk drive motor having the above structure, the rotor that is rotationally driven is
Central shaft 31, rotor case 32, drive magnet 33,
The drive pin 34, the chucking magnet 35, the index magnet 41, the hub base 42, and other components are included. Therefore, the assembly process is inevitably complicated, which hinders cost reduction.

Further, the index magnet 43 is
The index magnet 4 is attached to the surface of the rotor case 32 on the stator core 39 side.
3 may fall, which may adversely affect the characteristics of the motor.

The present invention has been made in order to solve the above problems of the prior art, and reduces the rotor assembly cost and prevents the index magnet from falling, and a method of manufacturing the same. The purpose is to provide.

[0011]

According to the first aspect of the present invention,
A rotatably supported center shaft, a rotor case that rotates integrally with the center shaft, a drive magnet fixed to the rotor case, and a drive that is installed in the rotor case and engages with an eccentric hole of the media hub to regulate the position of the media hub. A pin, a hub base provided on the upper surface of the rotor case for mounting a media hub,
It is a floppy disk drive motor equipped with a chucking magnet that is provided on the upper surface of the rotor case for magnetically attracting the media hub, and an index magnet that is provided on the lower surface side of the rotor case and on the inner peripheral side of the drive magnet. The hub base and the chucking magnet are integrally molded with a resin magnet, the rotor case is provided with a through hole, and the index magnet that penetrates the through hole and projects to the lower surface is integrally formed with the resin magnet. Characterize.

The invention according to claim 2 is characterized in that the hub base projects slightly from the chucking magnet in the axial direction and is not magnetized.

According to a third aspect of the present invention, a center shaft rotatably supported, a rotor case provided so as to rotate integrally with the center shaft, a drive magnet fixed to the rotor case, and a medium installed in the rotor case. A drive pin that engages with the eccentric hole of the hub to regulate the position of the media hub, a hub base that is provided on the upper surface of the rotor case and mounts the media hub,
Method of manufacturing a floppy disk drive motor including a chucking magnet provided on the upper surface of the rotor case for magnetically attracting the media hub, and an index magnet provided on the lower surface side of the rotor case on the inner peripheral side of the drive magnet The hub base and the chucking magnet are integrally molded with a resin magnet, and a through hole is formed in the rotor case, and an index magnet that penetrates the through hole and projects to the lower surface is integrally molded with the resin magnet. Is characterized by.

According to a fourth aspect of the present invention, when the hub base, the chucking magnet, and the index magnet are integrally molded with the resin magnet, the frequency power generation magnet is simultaneously integrally molded with the outer peripheral side of the rotor case. .

The non-magnetized portion of the resin magnet serves as a hub base to support a media hub such as a floppy disk, and the magnetized portion on the outer periphery of the hub base portion is a chucking magnet. Then, a media hub such as a floppy disk is adsorbed. Further, the portion of the resin magnet protruding toward the stator core serves as an index magnet for position detection.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a floppy disk drive motor and a method of manufacturing the same according to the present invention will be described below with reference to the drawings. In FIG. 1 and FIG. 2, the bearing holder 7 is placed in the hole 8 a formed in the center of the substrate 8.
It is fixed by caulking. The center portion of the bearing holder 7 is concave, and a hole 7c is formed in the center of the bottom plate 7a in this concave portion. The bearing 6 is fitted and fixed inside the concave portion of the bearing holder 7. The bearing 6 is a ball bearing, and the center hole of the inner ring communicates with the hole 7c of the bearing holder 7.

A stator core 9 is provided on the outer peripheral surface of the bearing holder 7.
Is attached. The stator core 9 is configured by laminating a plurality of magnetic plates, has a plurality of radially salient poles on the outer circumference, and has a coil 10 on the arm portion of each salient pole.
Is wound.

On the other hand, the center shaft 1 is fitted to the inner ring of the bearing 6. The central shaft 1 is rotatably supported by a bearing 6 with respect to a stator including a bearing holder 7, a stator core 9 and a substrate 8. A cup-shaped rotor case 2 is attached to the outer peripheral surface of the central shaft 1 above the bearing 6. The central portion of the upper surface of the rotor case 2 is a boss portion that projects toward the bearing 6, and the inner peripheral surface of this boss portion is attached to the outer peripheral surface of the central shaft 1.

A magnet 5 is mounted on the rotor case 2 and on the outer peripheral side of the central shaft 1. The magnet 5 has an opening angle of about 90 around the central axis 1.
And a small diameter portion 5y having an opening angle of about 270 ° about the central axis 1, and the large diameter portion 5x and the small diameter portion 5y are integrally formed.
The magnet 5 has a hole 5d in the center, and the edge portion of the hole 5d is not magnetized, and is a hub base 5a that projects slightly upward (axial direction) from other parts. Also,
The portion of the magnet 5 other than the hub base 5a, that is, the large diameter portion 5
The outer edges of x and the small diameter portion 5y are magnetized to form a chucking magnet 5b for attracting a media hub such as a floppy disk. Further, an arc-shaped elongated hole 5e is formed in a portion between the large diameter portion 5x and the hub base 5a, and a drive pin 4 described later is arranged in the elongated hole 5e.

Further, a protrusion is formed on the back surface side of the chucking magnet 5b of the magnet 5, that is, on the rotor case 2 side, and this protrusion is the rotor case 2.
An index magnet 5c used for position detection is formed by penetrating through a through hole formed in
It has become. The index magnet 5c is formed integrally with the magnetized chucking magnet 5b, and magnetized so that its magnetic pole is opposite to that of the adjacent chucking magnet 5b. For example, when the index magnet 5c is formed at the boundary between the N pole and the S pole of the chucking magnet 5b, the magnetic poles of the index magnet 5c are magnetized so as to have the S pole and the N pole. The index magnet 5 is attached to the portion where the magnetic pole of the chucking magnet 5b is the N pole.
If c is formed, the index magnet 5
The magnetic pole c is magnetized so as to be an S pole.

A support member 12 is attached on the upper surface of the rotor case 2 and inside the elongated hole 5e formed in the magnet 5. The support member 12 penetrates the rotor case 2 and projects toward the stator core 9 side. The swing arm 1 is attached to the stator core 9 side of the support member 12.
One end of 3 is attached. The swing arm 13 can be swung in a plane parallel to the plane of the magnet 5 by the support member 12. A drive pin 4 is attached to the other end of the swing arm 13. The drive pin 4 projects upward from a hole 2a provided in the rotor case 2. Further, the drive pin 4 has a groove on its outer peripheral surface, and this groove has a form in which the outer edge of the hole 2a is bitten. Since the hole 2a is set to be larger than the drive pin 4, the drive pin 4 can be moved within the hole 2a by swinging a swing arm (not shown). Such a drive pin 4 engages with an eccentric hole of a floppy disk (not shown) and drives the floppy disk to rotate as the central shaft 1 rotates.

A peripheral wall is provided on the outer periphery of the rotor case 2, and the rotor case 2 covers the bearing 6, the bearing holder 7, the stator core 9 and the like from above by the peripheral wall. The drive magnet 3 is attached to the inner surface of the peripheral wall. The inner peripheral surface of the drive magnet 3 faces the salient poles of the stator core 9 with a constant gap.
Therefore, when the coil 10 wound around the arm of the salient pole is energized, the drive magnet 3 is energized to drive the center shaft 1 and the hub base 2 on which a media hub such as a floppy disk is mounted, thereby driving the floppy disk. The disk is driven to rotate.

Further, a flange is formed on the peripheral wall of the rotor case 1 having the drive magnet 3 mounted on the inner peripheral surface thereof, and the frequency power generation magnet 11 is mounted on the lower end surface of the flange. A frequency power generation pattern is formed on the substrate 8 at a position facing the frequency power generation magnet 11 with a gap.

The magnet 5 used in the floppy disk drive motor is made of a resin magnet. A resin magnet is outsert-molded to the rotor case 2, the hub base 5a, the chucking magnet 5b, and the index magnet 5c are integrally molded from the outsert-molded resin magnet, and then the chucking magnet 5b is formed. The magnet 5 is formed by magnetizing the portion to be the index magnet 5c.

According to the above floppy disk drive motor, the hub base 5a and the chucking magnet 5 are provided.
Since the b and index magnets 5c are integrally formed of resin magnets, it is possible to reduce the number of parts and reduce the assembly cost. Further, since the magnet 5 including the hub base 5a, the chucking magnet 5b, the index magnet 5c, etc. is formed by performing outsert molding on the rotor case 2, this also contributes to the reduction of the assembly cost. can do.

Furthermore, the index magnet 5c protruding toward the stator core 9 side is the chucking magnet 5
Since it is formed integrally with b, it does not separate and fall even when vibration is applied from the outside, and the characteristics of the motor can be maintained for a long time.

Further, as shown in FIG. 3, the rotor case 2
It is also possible to reduce the size of the flange formed on the peripheral wall of the above, subject the reduced flange to outsert molding, and then magnetize it to form the frequency power generation magnet 20. Similarly, since the frequency power generation magnet 20 can be formed at the same timing as the magnet 5 formed by the outsert molding, the manufacturing time can be shortened and the assembling cost can be reduced.

In the above embodiment, a ball bearing such as a ball bearing is used as the bearing 6 that rotatably supports the central shaft 1, but the present invention is not limited to this, and a sintered oil-impregnated bearing may be used. . When a sintered oil-impregnated bearing is used for the bearing 6,
The center shaft 1 is inserted into the bearing 6 without being fitted and fixed. Further, although the motor of the above-described embodiment is a circumferentially opposed type motor, of course, it may be a surface opposed type motor. The same effect can be obtained even with a face-to-face type motor.

[0029]

According to the present invention, the hub base and the chucking magnet are integrally molded by the resin magnet, the rotor case is provided with the through hole, and the index magnet which penetrates the through hole and projects to the lower surface is provided. Since it is integrally molded with a resin magnet, the number of parts can be reduced,
It is possible to reduce the assembly cost. In addition, the hub base made of resin magnet and the chucking magnet are
Since it can be formed by outsert molding, it can contribute to the reduction of the assembly cost also from this point. Further, since the index magnet is integrated with the chucking magnet, the index magnet does not come off. Further, by forming the frequency power generation motor by outsert molding or the like, the frequency power generation motor can also be formed simultaneously with the integrally molded hub base, chucking magnet, index magnet, etc. It can contribute to the reduction of the assembly cost.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing an embodiment of a rotor applied to the above-mentioned floppy disk drive motor.

FIG. 3 is a sectional view showing another embodiment of a floppy disk drive motor according to the present invention.

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

[Explanation of symbols]

 1 central axis 2 rotor case 3 drive magnet 4 drive pin 5a hub stand 5b chucking magnet 5c index magnet

Claims (4)

[Claims] 1. A center shaft rotatably supported, a rotor case that rotates integrally with the center shaft, a drive magnet fixed to the rotor case, and an eccentric hole of a media hub installed in the rotor case. Drive pin for controlling the position of the media hub, a hub base mounted on the upper surface of the rotor case for mounting the media hub, a chucking magnet provided on the upper surface of the rotor case for magnetically attracting the media hub, and a rotor case for the rotor case. A floppy disk drive motor having an index magnet provided on the lower surface side and on the inner peripheral side of the drive magnet, wherein the hub base and the chucking magnet are integrally molded with a resin magnet, A through hole is formed in the case, and an index magnet that penetrates the through hole and projects to the lower surface is provided. Motor diskette drive, characterized by being integrally molded with serial resin magnet. 2. The motor for driving a floppy disk according to claim 1, wherein the hub base projects slightly from the chucking magnet in the axial direction and is non-magnetized. 3. A rotatably supported central shaft, a rotor case provided so as to rotate integrally with the central shaft, a drive magnet fixed to the rotor case, and an eccentricity of a media hub installed in the rotor case. A drive pin that engages with the hole to regulate the position of the media hub, a hub base that is provided on the upper surface of the rotor case and mounts the media hub, a chucking magnet that is provided on the upper surface of the rotor case and magnetically attracts the media hub, A method for manufacturing a floppy disk drive motor comprising an index magnet provided on the lower surface side of the rotor case and on the inner peripheral side of the drive magnet, wherein the hub base and the chucking magnet are made of resin. The rotor case is integrally formed with a magnet, and a through hole is formed in the rotor case. Method of manufacturing a motor for floppy disk drive, characterized in that the index magnet is integrally molded with the resin magnet that. 4. A floppy disk drive motor characterized in that, when a hub base, a chucking magnet and an index magnet are integrally molded with a resin magnet, a frequency power generation magnet is simultaneously integrally molded on the outer peripheral side of a rotor case. Production method.