JP2000116088A - Permanent magnet generator stored in diskette, and the diskette with generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent magnet generator with high output and a body thin enough to be assembled in a diskette and to provide a diskette with a generator. SOLUTION: A permanent magnet generator has a permanent magnet 212 rotating with a boss 211. The permanent magnet 212 includes a rotor 21 with a plurality of poles in a circumferential face and a plurality of magnetic teeth, made of soft magnetic material and arranged in a circumferential direction and extending flatly outward. Each magnetic tooth has a magnetic pole at its end in accordance with the magnetic pole of the permanent magnet 212 with a gap in between. The magnetic pole of the magnetic tooth and the other end thereof are joined with a back yoke. Each magnetic tooth has a stator 22 with a stator winding around it. The overall shape of the permanent magnetic generator is flat, and the thickness of the magnetic tooth extending outside in a flat shape is smaller than that of the permanent magnet. The permanent magnet generator can be incorporated into a 3.5-inch diskette.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet generator, and more particularly, to a permanent magnet generator which can be incorporated in a diskette inserted into a floppy disk drive.
The present invention relates to a permanent magnet generator that can be used as an input / output power source for a memory when the memory is incorporated in the diskette.

[0002]

2. Description of the Related Art Information such as the results of an individual's medical examination is stored in an IC card, and when visiting a medical institution with the IC card, medical treatment is performed based on the information in the IC card. Can be performed, and the contents of the medical chart at the time of medical treatment can be stored in the IC card. The use of IC cards as electronic money is also being considered. That is, a bank account, a personal identification number, and, if necessary, the account balance of a person who uses the IC card are stored, and each time money is used, communication settlement with the bank account is performed via the IC card.

[0003] In addition, since image information of a digital camera has a relatively large amount of information, it has been proposed to store it in a large-capacity flash memory. Since the flash memory has a capacity of several megabytes to 10 megabytes, you can store the image information of the digital camera in the flash memory and connect the flash memory to the personal computer to process it with the personal computer, By storing the result in a flash memory, an additional external storage device such as an MO is not required.

[0004] Both the IC card and the flash memory require a unique device as their input / output device, and this necessity has hindered their spread. A floppy disk drive, especially a 3.5 ″ floppy disk drive is generally used as an input / output device of a computer, particularly a personal computer widely used.
The use of a 3.5 "floppy disk drive for input and output of a memory card such as an IC card or a flash memory is expected to spur the spread.
It is also considered to use a 3.5 "floppy disk drive to input / output a memory card.
An adapter that can be inserted into a floppy disk drive and incorporated has also been proposed. However, the 3.5 "floppy disk drive rotates the floppy disk at 300 rpm between a 3.5" diskette inserted therein (a normal 3.5 "floppy diskette) and a magnetic head for inputting / outputting information. Drive shaft, but no power supply terminal, so the diskette-shaped adapter built into the adapter
As a power source for the PU, a button-type battery is used in the adapter. However, since the battery is consumed with use, it needs to be replaced every few months at the longest.

[0005] Therefore, if a generator is incorporated in the diskette and the generator can be operated using the rotation of the drive shaft of a 3.5 "floppy disk drive, it becomes extremely useful. In fact, it has already been proposed to incorporate the generator in a 3.5 ″ diskette, as disclosed in Japanese Patent Publication No. 7-86912 and PCT International Publication No. It is described in Table 7-500238.

Japanese Patent Publication No. 7-86912 discloses that a generator is incorporated in a 3.5 ″ diskette, and that the generator has a rotor, a stator, and a regulator.
Its detailed configuration is not shown. Also, Tokiohei 7-5002
No. 38 has a permanent magnet that rotates with the boss as a generator built into a 3.5 ″ diskette, and the boss with the permanent magnet is rotated by a drive shaft of a floppy disk drive. The permanent magnet has a cylindrical shape and is magnetized in the direction of the rotation axis so that there are a large number of magnetic poles on the cylindrical end surface.The magnetic pole of the stator yoke sandwiches the cylindrical permanent magnet. And the stator coils are provided between the stator yokes on both sides of the cylindrical permanent magnet.
There is also shown an example in which magnetic poles are provided on the circumferential surface of the cylindrical permanent magnet, in which case the magnetic poles of the stator yoke are claw-pole type.

[0007]

As described above, these publications describe the incorporation of a permanent magnet generator into a 3.5 "diskette. Since the detailed structure of the rotor and the detailed structure of the stator are not described, it is unclear what output has been obtained.

A permanent magnet generator sized to be incorporated into a 3.5 "floppy diskette as disclosed in Japanese Patent Publication No. 7-500238, and a cylindrical rotor permanent magnet. Consider a magnet that is magnetized in the direction of the axis of rotation so as to have a large number of magnetic poles on the end face of the cylinder, where stator poles are arranged on both sides of the end face of the cylinder via small magnetic gaps. Allowed thickness is 2.0
~ 2.5mm, so the permanent magnet thickness is 0.5 ~
Only 0.8 mm is allowed. As described above, a magnet having a short distance between magnetic poles has a small magnetomotive force even if a magnet having a large coercive force is used. In addition, when the magnetomotive force is increased by increasing the thickness of the magnet, the thickness allowed for the stator magnetic pole is reduced, and the magnetic flux cannot be sufficiently transmitted.

In the case of a permanent magnet generator in which a magnetic pole is provided on a circumferential surface of a cylindrical permanent magnet and a stator yoke opposed thereto is a claw pole type, both claw poles are provided. The end yokes of the magnetic poles are provided facing each other in the thickness of 2.0 to 2.5 mm allowed for the generator, and the stator winding is applied between the yokes at both ends. The allowable length of the stator winding is 1 mm or less, and the output voltage is low because a sufficient number of windings cannot be provided.

Accordingly, an object of the present invention is to provide a thin permanent magnet type generator which can be incorporated in a diskette and which can obtain a sufficient output.

It is another object of the present invention to provide a permanent magnet generator which can be put into a diskette having a structure which is easy to assemble.

According to the present invention, by reducing the cogging torque of the generator, the diskette can be smoothly rotated even by a low-torque drive source such as a 3.5 "floppy disk drive to obtain a stable output. It is another object to provide a permanent magnet generator for ingress.

Another object of the present invention is to provide a diskette incorporating a permanent magnet generator.

According to the present invention, even if the relative position between the diskette and the floppy disk drive is shifted, the entire generator is adjusted with respect to the diskette which receives the diskette in accordance with the position of the drive shaft of the floppy disk drive. It is another object of the present invention to provide a diskette having a permanent magnet generator having a structure capable of performing the operation.

Further, the present invention provides a diskette having a permanent magnet generator in which the leakage magnetic field from the generator is reduced to such an extent that it does not adversely affect a memory card or the like placed in a diskette alongside the generator. It is also intended to be.

[0016]

SUMMARY OF THE INVENTION A permanent magnet generator for putting in a diskette according to the present invention has (1) an annular permanent magnet that can rotate with a boss, and the permanent magnet is disposed on a circumferential surface. A rotor having a plurality of rotor magnetic poles arranged side by side, these magnetic poles having different polarities in a circumferential direction, and (2) a stator having a plurality of magnetic pole teeth made of a soft magnetic material; In the permanent magnet type generator having the above, each magnetic pole tooth of the stator is (I) a stator magnetic pole that can face each rotor magnetic pole provided on the circumferential surface via a magnetic gap. At one end, (II) extends planarly outward from the stator poles, and the stator coil is wound, and (III) the end opposite to the stator poles is adjacent The opposite ends of the magnetic pole teeth are connected to each other by a back yoke, and Wherein with the stator is configured as a whole flat plate, the thickness of the rotation axis direction of the stator magnetic pole is characterized by less than the thickness of the rotation axis direction of the permanent magnets and.

In the permanent magnet type generator for putting in the diskette, the magnetic poles of the permanent magnet of the rotor on the circumferential surface are arranged at substantially equal angular intervals, and the number of poles is It has 12 to 24 poles, and each magnetic pole of the magnetic pole teeth of the stator can be provided so as to be able to face each of the magnetic poles of the rotor. At this time, it is preferable that the back yoke has an annular shape.

As the back yoke, a back yoke made of a soft magnetic material having a flat contact surface in the direction of the rotation axis is provided at each of both end faces in the rotation axis direction at the end opposite to the magnetic pole of the magnetic pole teeth in the radial direction. Preferably, the magnetic pole teeth are fixed to connect between the opposite ends of the magnetic pole teeth. Alternatively, the back yoke may surround a plate material having a U-shaped cross section at the end in the radial direction opposite to the magnetic pole of the magnetic pole teeth, and press-fit to connect the opposite end.

Further, in the permanent magnet generator for putting in the diskette, the magnetic poles of the permanent magnet of the rotor on the circumferential surface are arranged at substantially equal angular intervals,
The number of poles is 12 to 24, and each magnetic pole of the magnetic pole teeth of the stator can be provided so as to be able to face each magnetic pole except at least one of the rotor magnetic poles.

Further, the magnetic pole teeth of the stator of the permanent magnet type generator have (I) a stator magnetic pole at one end thereof, and the stator magnetic pole has at least one of the rotor magnetic poles. Are provided at substantially equal angular intervals on the circumference except for the portion facing the at least one pole so that they can face the magnetic poles except for (I).
(I) the stator poles extending planarly outward from the stator poles, the stator coils being wound, and (III) magnetic pole teeth having stator poles provided at substantially equal angular intervals. The opposite ends can be connected by a back yoke made of a soft magnetic material.

In the permanent magnet type generator to be put in the diskette, the thickness of the magnetic poles of the stator magnetic pole teeth in the rotation axis direction is greater than the thickness saturated by the magnetic flux emitted from the permanent magnet of the rotor. Is preferred. The permanent magnet of the rotor preferably has a length in the direction of the rotation axis of 2.0 mm or less.

The permanent magnet of the rotor used in the permanent magnet generator for putting in the diskette of the present invention can have an easy axis of magnetization in the radial direction. Also,
The permanent magnet of the rotor can have an easy axis of magnetization in a direction connecting adjacent magnetic poles of different polarities on its circumference. Preferably, the permanent magnet of the rotor is a sintered NdFeB magnet. The permanent magnet of the rotor is Nd
A material obtained by solidifying the powder of the FeB magnet with a binder can be used.

In the permanent magnet type generator for putting in the diskette, adjacent stator magnetic poles facing the permanent magnet at the tip of the magnetic pole teeth of the stator may be connected to each other by an inner yoke. it can. Also, at this time, it is preferable that the inner yoke connecting the adjacent stator magnetic poles at the tip of the magnetic pole teeth has the thinnest portion at the center between the adjacent stator magnetic poles. It is preferable that the cross-sectional area of the central part between the adjacent stator magnetic poles is smaller than the cross-sectional area of the magnetic pole teeth. It is preferable that the inner yoke is connected by a taper or an arc from the magnetic pole toward the thinnest portion at the center between the adjacent magnetic poles.

A diskette incorporating the permanent magnet generator of the present invention is a diskette having a diskette case and a permanent magnet generator provided in the diskette case, wherein the permanent magnet generator is (1) It has an annular permanent magnet that can rotate with the boss, and the permanent magnet has a plurality of rotor magnetic poles arranged on a circumferential surface, and these magnetic poles have different polarities in the circumferential direction. And (2) a stator having a plurality of magnetic pole teeth made of a soft magnetic material, and each of the magnetic pole teeth of the stator comprises: (I) each of the rotations provided on the circumferential surface; A stator pole at one end thereof, which can be opposed to the stator pole via a magnetic air gap, and (II) extending planarly outwardly from the stator pole and having a stator coil wound therearound. , (I
II) The end opposite to the stator magnetic pole is connected to the opposite end of the adjacent magnetic pole tooth by a back yoke, and the rotor and the stator are configured as a flat plate as a whole. In addition, the thickness of the stator magnetic pole in the rotation axis direction is smaller than the thickness of the permanent magnet in the rotation axis direction.

In the diskette incorporating the permanent magnet generator, the magnetic poles of the permanent magnet of the rotor on the circumferential surface are arranged at substantially equal angular intervals, and the number of poles is 12 to There are 24 poles, and each magnetic pole of the magnetic pole teeth of the stator can be provided so as to be able to face each of the magnetic poles of the rotor. At this time, it is preferable that the back yoke has an annular shape. In the diskette incorporating the permanent magnet type generator, the magnetic poles of the permanent magnet of the rotor on the circumferential surface are arranged at substantially equal angular intervals, and the number of poles is 12 to 24 poles. The magnetic poles of the magnetic pole teeth of the stator can be provided so as to be able to face the magnetic poles of the rotor except at least one of the magnetic poles.

Further, in the diskette incorporating the permanent magnet generator, the magnetic pole teeth of the stator of the permanent magnet generator have (I) a stator pole at one end thereof, and the stator pole is The magnetic poles are provided at substantially equal angular intervals on the circumference except for a portion facing the at least one pole so as to be able to face each magnetic pole except at least one of the sub-poles, and ( II) The stator coil extends around the stator poles in a plane outwardly and planarly, and (I)
II) The magnetic pole teeth having stator magnetic poles provided at substantially equal angular intervals can be connected between the magnetic pole and the opposite end by a back yoke made of a soft magnetic material.

In the diskette incorporating the permanent magnet generator, the thickness of the magnetic poles of the stator magnetic pole teeth in the rotation axis direction is as follows:
It is preferable that the thickness be greater than or equal to the thickness saturated by the magnetic flux emitted from the permanent magnet of the rotor. The permanent magnet of the rotor preferably has a length in the direction of the rotation axis of 2.0 mm or less.

The permanent magnet of the rotor used in the diskette incorporating the permanent magnet generator of the present invention can have an axis of easy magnetization in the radial direction. Also,
The permanent magnet of the rotor can have an easy axis of magnetization in a direction connecting adjacent magnetic poles of different polarities on its circumference. Preferably, the permanent magnet of the rotor is a sintered NdFeB magnet. The permanent magnet of the rotor is Nd
A material obtained by solidifying the powder of the FeB magnet with a binder can be used.

In the diskette incorporating the permanent magnet generator, adjacent stator magnetic poles facing the permanent magnet at the tip of the magnetic pole teeth of the stator can be connected to each other by an inner yoke. In this case, it is preferable that the inner yoke connecting the adjacent stator magnetic poles at the tip of the magnetic pole teeth has the thinnest portion at the center between the adjacent stator magnetic poles. Preferably, in the inner yoke connecting the adjacent stator magnetic poles at the tips of the magnetic pole teeth, a cross-sectional area of a central portion between the adjacent stator magnetic poles is smaller than a cross-sectional area of the magnetic pole teeth.

The diskette incorporating the permanent magnet type generator may further include a memory card insertion space provided in the diskette case. At this time, the memory card insertion space and the permanent magnet generator overlap at least partially, and at least a part of the boundary wall can be a magnetic shield plate. Further, the boundary wall may be a housing of a permanent magnet type generator.

A diskette incorporating the permanent magnet type generator according to the present invention, wherein a holding mechanism capable of absorbing eccentricity of the permanent magnet type generator with respect to the diskette case is provided in the diskette case. It can be.

In the diskette incorporating the permanent magnet generator according to the present invention, any one of an input / output terminal of the diskette, a card contact terminal, and a memory card insertion space between stator magnetic pole teeth which are not connected to each other by a back yoke. Can be provided. That is, it can be said that the back yoke is cut at at least one of the input / output terminal of the diskette, the card contact terminal, and the memory card insertion space.

In the diskette incorporating the permanent magnet generator of the present invention, it is preferable that the boss of the permanent magnet generator can be engaged with a drive shaft of a disk drive.

[0034] In the present invention, the diskette includes the following items:
It is preferable to have a structure that can be attached to a 5 ″ floppy disk drive.

Preferably, a magnetic shield plate is provided on at least one side surface of the permanent magnet rotor of the permanent magnet generator according to the present invention.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a permanent magnet generator according to the present invention and a diskette incorporating the permanent magnet generator will be described in detail with reference to the drawings.

FIG. 1 shows a diskette having a permanent magnet generator according to the present invention. FIG. 1 (a) is a plan view (bottom view) of the diskette, and FIG. 1 (b) is 1B-1B of FIG. 1 (a). Sectional view,
FIG. 1 (c) is a partially enlarged view of FIG. 1 (b). Figures 2-5
FIG. 2 shows the diskette of FIG. 1 and a permanent magnet generator incorporated therein, FIG. 2 is a perspective view showing a state in which the cover of the diskette is opened, and FIG. 3 is an exploded perspective view of the diskette and the permanent magnet generator. FIG. 4 is an exploded perspective view of the permanent magnet generator shown in FIG. FIG. 5 is an exploded perspective view showing the stator portion in an enlarged manner.

FIG. 6 is a perspective view of a permanent magnet of a rotor used in the permanent magnet generator of the present invention, and FIG. 7A is a permanent magnet of the rotor having an axis of easy magnetization in a radial direction. FIG. 7 (b) is a plan view of a rotor (radial anisotropy), and FIG. 7 (b) shows a permanent magnet of a rotor having an axis of easy magnetization in a direction connecting adjacent different poles on its circumferential surface ( (Polar anisotropy).

FIG. 8 is a sectional view taken along line 8-8 in FIG. 2 and shows the relationship between the thickness of the stator magnetic pole teeth in the rotation axis direction and the length of the rotor permanent magnet in the rotation axis direction. FIG. 9 (a) is a plan view of a circular plate-shaped stator, and FIG. 9 (b) is a plan view of a notched stator. FIG. 10 is a partially enlarged view of the stator.
FIG. 4A is a plan view of a portion of the stator showing the closed slots and FIG. 4B showing the angles of the teeth of the yoke connecting the adjacent magnetic poles at the pole tip.

FIG. 11 is a plan view showing a state where a cover of a diskette having the permanent magnet type generator of the present invention is removed, and shows a state where the permanent magnet type generator is supported by a spring in the diskette. I have. FIG. 12 is an exploded perspective view showing one embodiment of a rotor bearing structure. FIG. 13 is a plan view of a permanent magnet type generator according to the present invention having a sliding bearing at a portion where the permanent magnet rotor and the stator face each other. FIG. 14 shows a friction coefficient at a portion where the permanent magnet rotor and the stator face each other. 1 is a plan view of a permanent magnet type generator according to the present invention having a small layer as a bearing.

FIG. 15 is a BH curve characteristic diagram of the permanent magnet (sintered NdFeB and NdFeB bonded magnet) used in the present invention, in which a permeance coefficient is inserted.

FIG. 16 shows a sintered Nd as a rotor permanent magnet.
FIG. 4 is a graph showing the amount of magnetic flux per pole when the number of poles is changed, using the thickness of the stator as a parameter, in the permanent magnet generator of the present invention using the FeB radial anisotropic permanent magnet. Reference numeral 17 denotes the same generator as in FIG. 16, wherein the output voltage when the stator thickness is 1.0 mm and the number of poles is changed is 100%, and the relative output voltage when the number of poles is changed is a parameter of the stator thickness. FIG. 18 is a graph showing the same output voltage (when the number of turns of the coil per stator magnetic pole is the same) and FIG. A graph showing the relative output voltage when the number of poles is changed, assuming 100%, using the thickness of the stator as a parameter (the number of turns of the coil per stator magnetic pole is changed according to the stator space). is there.

FIG. 19 shows a sintered Nd as a rotor permanent magnet.
In the permanent magnet generator of the present invention using the FeB polar anisotropic permanent magnet, the amount of magnetic flux per pole when the number of poles is changed,
FIG. 20 is a graph showing the thickness of the stator as a parameter, and FIG. 20 shows the same generator as in FIG. The number of turns per coil is changed according to the stator space), and the output voltage when the stator is 1.0 mm and the thickness is 1.0 mm with 20 poles using a sintered NdFeB radially anisotropic permanent magnet is defined as 100%. FIG. 21 is a graph showing
With the same generator as in FIG. 19, the relative output voltage when the number of poles was changed was used as the parameter for the thickness of the stator (assuming the same number of turns of the coil per one magnetic pole of the stator).
6 is a graph showing the output voltage assuming 100% when the stator is 1.0 mm thick with 20 poles using the radially anisotropic permanent magnet B.

FIG. 22 shows that NdFe is used as a rotor permanent magnet.
FIG. 23 is a graph showing the amount of magnetic flux per pole when the number of poles is changed using the thickness of the stator as a parameter in the permanent magnet generator of the present invention using the bonded permanent magnet of FIG.
In the same generator as in FIG. 22, the relative output voltage when the number of poles is changed is changed using the thickness of the stator as a parameter (the number of turns of the coil per one magnetic pole of the stator is changed according to the stator space). 24) is a graph showing the output voltage as 100% when the stator is 1.0 mm in thickness with 20 poles using a radially anisotropic permanent magnet of sintered NdFeB, and FIG.
2, the relative output voltage when the number of poles was changed and the thickness of the stator was used as a parameter (with the same number of turns of the coil per one magnetic pole of the stator) to obtain a sintered NdFeB
4 is a graph showing the output voltage when the stator voltage is 20 mm and the stator thickness is 1.0 mm, using the radially anisotropic permanent magnet of FIG.

FIG. 25 is a graph showing the cogging torque with respect to the angle of the teeth of the inner yoke in the permanent magnet generator of the present invention using the radially anisotropic permanent magnet of sintered NdFeB. 5 is a graph showing cogging torque with respect to the angle of the teeth of the inner yoke in the permanent magnet generator of the present invention using the polar anisotropic permanent magnet of FIG.

FIG. 27 is a diagram showing an output waveform of the permanent magnet generator of the present invention.

FIG. 28 is a graph showing the intensity of the leakage magnetic field with respect to the distance from the side surface of the diskette having the permanent magnet generator of the present invention, as compared with the case without the magnetic shield.

First, the structure of the permanent magnet generator of the present invention and the structure of a diskette incorporating the same will be described. Here, a description will be made using a diskette structured to be attached to the most widely used 3.5 "floppy disk drive, but it will be apparent from the following description that the present invention can be applied to diskettes having other sizes or structures. 3.5 "diskette (usually
3.5 "floppy disk) 1
Has a structure shown in a plan view (bottom view) in FIG. 1A, and is a plastic case having a length of 94 mm, a width of 90 mm, and a thickness of 3.5 mm. One end of the case has an opening 13 for a magnetic head for input / output to enter, and a front portion to be attached to the floppy disk drive has a slidable cover 14, which can be opened and closed. At the approximate center of the case, there is a boss 211 capable of transmitting the rotation of the drive shaft of the floppy disk drive. In the case of a floppy disk, a floppy disk is mounted coaxially with this boss so that it can rotate. ing.

In the diskette 1 incorporating the permanent magnet generator of the present invention, the permanent magnet generator 2 is incorporated around the center boss 211 of the diskette 1, and the rotor 21 of the generator 2 It comprises a boss 211 and an annular permanent magnet 212 attached to the outer periphery of the boss 211 and capable of rotating with the boss 211. The stator 22 of the generator includes a rotor permanent magnet 21.
2 is provided with a magnetic gap between the outer periphery of the permanent magnet 212 and the outer peripheral surface of the permanent magnet 212, and is attached inside the diskette. The diskette 1 shown in the figure is used as a memory card input / output device, and therefore has a space 15 into which a memory card can be inserted, and a card contact terminal 16 for exchanging information with the memory card. Have been. An input / output terminal 17 for exchanging information between the diskette and the magnetic head of the floppy disk drive is provided at an opening 13 opened for the magnetic head to enter. A CPU 18 is provided as needed to process information between the input / output terminal 17 and the card contact terminal 16. Permanent magnet generator 2 is C
It is used as a power supply for driving the PU 18 and for driving the card contact terminals 16 and the like. However, the electricity from the generator may include ripples and the like, and requires rectification and stabilization. It is incorporated in the output line of the generator 2 provided in the diskette.

The boss 211 of the rotor 21 of the permanent magnet type generator 2 is engaged with the drive shaft of the floppy disk drive, and the rotor 21 is rotated by the rotation of the drive shaft. In the case of a 3.5 "floppy disk drive, the rotational speed is usually 300 rpm. Since the boss 211 engages with the drive shaft of the floppy disk drive, the structure of the engaging portion of the boss 211 with the drive shaft is as follows. It is preferable to keep the structure of the boss of a normal diskette the same.

FIG. 1A shows a permanent magnet type generator 2 with a broken line.
Input / output terminal 17 and card contact terminal 16
However, if the outer circumference of the stator yoke 221 of the permanent magnet type generator 2 is a perfect circle, the outer circumference of the stator yoke 221 and these input / output terminals 17 and card contact terminals 16 May interfere. Therefore, it is preferable to cut out the outer periphery of the stator yoke 221 at these portions.

The size of a memory card is often the same as that of a normal credit card, and has a length of eight.
5 mm, width 54 mm, thickness 0.8 mm. When the space 15 for storing the memory card is provided on the diskette 1, the space 15 overlaps with the permanent magnet generator 2 incorporated as shown in FIGS. If the thickness of the plastic case cover on both sides is two in 3.5mm,
When the thickness of the memory card is 0.8 mm and there is a margin for inserting and removing the memory card, the thickness of the generator 2 is at most 2.3 mm. From these, the size of the generator 2 is, for example, about 55 mm in outer diameter and 2 mm in thickness,
Since the size of the rotor 21 is 25 mm in boss diameter, the outer diameter of the rotor 21 is about 30 mm.

A magnetic shield plate is inserted between the memory card insertion space 15 and the generator 2, and
It is preferable that a magnetic shield plate is also provided on the back side of the diskette cover in contact with the generator. Generator 2
Is preferably made of a magnetic shield plate. The thickness of the magnetic shield plate used here is at most 0.
It is 2 mm, preferably 0.1 mm or less. Since it is necessary to prevent the magnetic field leaking from the generator 2 to the outside of the memory card space 15 or the diskette 1 with such a thin magnetic shield plate, it is preferable that the generator 2 has a structure having as little leakage magnetic field as possible. . Since the permanent magnet generator 2 of the present invention is an inner rotor type, it has a small leakage magnetic field.

When the space 15 for inserting a memory card or the like is provided in the 3.5 "diskette 1, the thickness allowed for the generator 2 has been described above, but depending on the application, the 3.5" diskette may be used. In some cases, the space 15 such as a memory card is not required. In that case, the thickness of the generator 2 can be increased to about 3 mm. If the diskette is slightly thicker than the 3.5 "diskette 1, for example, 4.0 to 4.0"
When the thickness becomes 5.0 mm, the thickness allowed for the generator 2 can be 3.5 to 4.5 mm.

FIGS. 2 to 5 show a permanent magnet generator of the present invention. FIG. 2 is a perspective view showing a state in which a diskette cover is opened. FIG. 3 is an exploded perspective view of the diskette and the permanent magnet generator. FIG. 4 and FIG. 4 are exploded perspective views in which the permanent magnet generator shown in FIG. FIG.
FIG. 4 is an exploded perspective view showing the stator portion in an enlarged manner. Here, the permanent magnet generator 2 is provided between the front plate 11 and the back plate 12 of the diskette cover. The generator 2 is located at the opening in the center of the back plate 12 of the diskette cover.
Boss 211 faces. The generator 2 is installed in a housing 23 made of a cup-shaped magnetic shield plate or the like. In this figure, the housing 23 is screwed to the back of the diskette cover through screw holes 231 at the four corners. The generator includes a flat rotor 21 at the center and a flat stator 22 provided with a magnetic gap between the outer circumference of the rotor and the outer circumference of the rotor. The child 21 has a plate-like configuration as a whole. The flat stator 22 includes a housing 23.
It is fixed to the inner circumference of. A shaft 232 for supporting the rotor is provided at the center of the housing 23. The boss 211 of the rotor 21 is supported by an oil-impregnated bearing 213 made by sintering a copper alloy powder or the like so that the boss 211 can rotate with respect to the shaft 232. Boss 211 is adapted to engage the drive shaft of a 3.5 "floppy disk drive, as previously described, and has a size of about 25
Preferably, it has a diameter of mm. An annular permanent magnet 212 is fixed to the outer periphery of the boss 211, and the permanent magnet 212 has a plurality of magnetic poles on its outer circumferential surface, and these magnetic poles have different polarities in the circumferential direction, that is, NSNS ……… lined up.

The stator 22 has a plurality of magnetic pole teeth 223 radially projecting around an annular inner yoke 222. In other words, the magnetic pole teeth 223
The stator magnetic pole facing the outer periphery of the rotor is coupled by an inner yoke 222 between its adjacent stator magnetic poles. However, the cross-sectional area of the inner yoke 222 between the stator magnetic poles is made smaller than the cross-sectional area of the magnetic pole teeth 223 of the stator, and most of the magnetic flux emitted from the rotor 21 passes through the stator magnetic pole teeth 223. It is going to pass.
These magnetic pole teeth 223 also have an annular shape as a whole,
An annular back yoke 22 having a flat end face in the rotation axis direction on both sides of the outer circumference end face of the magnetic pole teeth 223 in the rotation axis direction.
4, 224 'are fixed. Back yoke 224,
224 'is most preferably provided on both end faces in the rotation axis direction at the outer peripheral end of the magnetic pole tooth 223 and the end opposite to the magnetic pole. However, the magnetic pole teeth 223 may be provided on one surface in the rotation axis direction at the outer peripheral end, or a U-shaped annular back yoke may be provided so as to surround the outer peripheral end surface of the magnetic pole teeth 223.

The magnetic resistance between each of the magnetic pole teeth 223 and the back yokes 224, 224 'connecting the outer peripheral ends of the magnetic pole teeth 223 must be as small as possible. In the preferred embodiment of the permanent magnet generator 2 of the present invention, the stator yoke 221 having a plurality of magnetic pole teeth 223 radially extending around the annular inner yoke 222 is used. It is essential to attach the back yoke 224. Such a stator yoke 221
As shown in FIG. 5, the coil can be assembled simply by inserting the coil 225 wound in advance from the outside of the magnetic pole teeth 223, so that the assembling work is facilitated. However, after that, the back yokes 224 and 224 'are
Since it is attached to the outer periphery of the magnetic pole teeth 223, attaching the back yokes 224, 224 'to the end faces of the outer peripheral ends of the magnetic pole teeth 223 in the direction of the rotation axis may be said to be easy in assembling. Further, at least 0.2-0.5 .mu.m irregularities are formed on the surfaces of the back yokes 224, 224 'to be brought into contact with the end faces of the magnetic pole teeth. For this purpose, it is preferable to attach the back yoke from the end face. It is also possible to fit an annular back yoke on the outer peripheral end of the magnetic pole teeth, but in this case, the back yoke may be deformed or the inner yoke integrated with the magnetic pole teeth may be deformed.

The magnetic pole teeth 223 of the stator 22 and the inner yoke 22
2. Both the back yoke 224 is made of a soft magnetic material. Since a large saturation magnetic flux density Bs is preferable from the viewpoint of reducing the cross-sectional area of parts and reducing the size of the entire generator, soft iron, magnetic soft iron having a saturation magnetic flux density Bs of 1.2T or more, and A silicon steel sheet containing a magnetic core and 4 to 6% Si can be used. A stator coil 225 for taking out an output is wound around each magnetic pole tooth 223. Since this generator 2 has a flat plate shape as a whole and needs to be 2 mm or less even at the thickest point, the outermost diameter of the stator coil 225 wound around the magnetic pole teeth 223, that is, the thickness in the rotation axis direction Needs to be 2 mm or less.

As described above, the permanent magnet 212 used for the rotor 21 is preferably an annular permanent magnet.
The permanent magnet 212 is fixed to the outer periphery of the boss 211 with an adhesive or the like. This annular permanent magnet has an appropriate length, that is, a thickness in the direction of the rotation axis. The thickness of the permanent magnet is at most 2.0 mm, and can be used in the range of 0.8 to 2.0 mm, preferably 1.0 to 1.9 m.
m. However, it will be apparent that this size will vary depending on the size of the diskette used and the configuration of the equipment to be incorporated. As shown in the perspective view of FIG. 6, the permanent magnet 212 has magnetic poles on its outer peripheral surface.

It is desirable from the viewpoint of magnetomotive force that the annular permanent magnet 212 be as thick as possible in the direction of magnetization. In the case of having the radial anisotropy shown in FIG.
If the boss 211 is made of a ferromagnetic material, the magnetic force lines entering the magnet in the radial direction from adjacent magnetic poles on the circumferential surface enter the ferromagnetic boss 211 in the radial direction from the opposite polarity magnetic pole. Connect to the magnetic field lines. In the case of the polar anisotropy shown in FIG. 7B, lines of magnetic force connect magnetic poles of opposite polarities inside the magnet. In any case, the thickness of the permanent magnet 212 in the radial direction may be 1/3 to 1/4 or more of the distance between the magnetic poles, but is preferably 2 mm or more.

As a material of the permanent magnet 212, a sintered NdFeB magnet is preferable. In spite of being a permanent magnet having a relatively small thickness (relatively thin in the direction of magnetization), a large reverse magnetic field is applied and a demagnetizing coefficient is large in shape. A material having a large coercive force and a large magnetic flux density is preferred. Although the sintered NdFeB magnet has magnetic anisotropy, FIG.
As shown in FIG. 7 (a), one having an easy axis of magnetization in the radial direction, that is, having a radial anisotropy, and one adjacent magnetic pole of different polarity on the circumferential surface as shown in FIG. 7 (b). Those having an easy axis of magnetization in the connecting direction, that is, those having polar anisotropy are preferable. N which is called NdFeB bonded magnet
A material obtained by combining dFeB magnet powder with a plastic binder or the like can also be used. However, in the case of a bonded magnet, the ratio of the magnet component is smaller than that of a sintered NdFeB magnet.
The generated magnetic flux becomes smaller. However, if the required output is small, a permanent magnet generator made with bonded magnets may be sufficient.

As the permanent magnet of the permanent magnet generator of the present invention, besides the NdFeB magnet, (1) a nitride magnet such as S
(3) N magnets such as mFeN magnets, (2) magnets containing α-iron in SmFeN called exchange spring magnets, magnets containing α-iron in NdFeB, magnets containing Fe ₃ B in NdFeB, etc.
HDDR (hydrogenation, decomposition, etc.)
Dehydrogenation / recombination) magnets, (4) SmCo magnets and the like can also be used in view of the required characteristics.

FIGS. 6 and 7 (a) and 7 (b) show an annular permanent magnet 212 having 24 magnetic poles on the outer peripheral surface.
The number of poles is preferably from 24 to 24, and more preferably from 16 to 20. When the number of poles is small, the amount of magnetic flux per pole increases, but the maximum output of the generator is 16 to 24 poles. However, as the number of poles increases, the space between the magnetic pole teeth extending in the radial direction of the stator decreases, and the number of turns of the coil of the magnetic pole teeth decreases. In addition, there are problems such as difficulty in manufacturing the stator and distortion of the output voltage waveform.
Zero pole is optimal.

The magnetic poles of the stator magnetic pole teeth extending in the radial direction are:
It is preferable that the number of poles is the same so that the magnetic poles of the rotor permanent magnet can be opposed to each other via the magnetic air gap.

When the number of poles is the same, the magnetic pole thickness of the stator magnetic pole teeth 223 extending in the radial direction needs to be smaller than the length of the permanent magnet 212 in the rotation axis direction, that is, the thickness. By making the thickness of the stator magnetic pole teeth 223 smaller than the thickness of the permanent magnet, a large output can be obtained as the generator 2. However, the stator magnetic pole teeth 22
The thickness of the magnetic pole 3 needs to be thick enough not to be saturated by the magnetic field lines emitted from the permanent magnet 212. FIG. 8 shows the stator 22 and the rotor 21 of the permanent magnet generator 2 of the present invention.
And the thickness t1 and the magnet thickness t2 of the stator magnetic pole teeth extending in the radial direction. In this figure, t1 <
It needs to be t2. This is because the lines of magnetic force from the magnetic poles of the permanent magnet 212 are guided as much as possible into the magnetic pole teeth 223 extending in the radial direction that constitute the stator 22, and the magnetic flux density in the magnetic pole teeth is increased. When the magnetic flux density of the permanent magnet 212 is compared with the saturation magnetic flux density of the stator 22, as described above, the stator 2
2 is made of a soft magnetic material and has a saturation magnetic flux density of 1.2 T or more, while the permanent magnet 212 has a residual magnetic flux density of 1.000 even if it is a sintered NdFeB magnet having the strongest magnetic force. Since it is 2 to 1.3 T, the magnetic flux density at the operating point is about 1.0 T. The permanent magnet used in the rotor of the permanent magnet generator according to the embodiment of the present invention described later has a permeance coefficient of 2 before being incorporated into the generator and about 5 in the assembled state. The maximum magnetic flux density is 1.02T. The magnetic flux density passing through the magnetic pole teeth 223 is increased by reducing the thickness t1 of the magnetic pole teeth 223 extending in the radial direction of the stator 22 and reducing the cross-sectional area thereof. When the sintered NdFeB magnet is used as the rotor permanent magnet 212 and the stator 22 having a saturation magnetic flux density of 1.2 T or more is used, 30% to 70% of the thickness of the permanent magnet is used.
% Pole teeth 223 are preferred. That is,
When a sintered NdFeB magnet having a thickness of 1.6 mm is used for the rotor 21, the output is large when t1 is 0.5 mm, 0.7 mm, and 1.0 mm as described in an experiment described later.

Here, the structure of the stator 22 will be described in detail. FIG. 9A is a plan view showing the stator 22 in the shape of a circular flat plate.
FIG. 9 (b) shows an example in which 6, 226 'are provided. The magnetic pole teeth 223 extending in the radial direction are provided at substantially equal intervals on the inner peripheral surface of the stator 22 with magnetic poles, and face the rotor permanent magnet 212 via the magnetic gap as described above. ing. The magnetic pole at the inner end of the magnetic pole tooth 223 extending in the radial direction is connected to the adjacent magnetic pole by an inner yoke 222 as shown in an enlarged manner in FIG. In a preferred embodiment of the present invention, the inner yoke 22
2 and the magnetic pole teeth 223 are made of an integrated soft magnetic plate. As described above, since the cross-sectional area of the inner yoke 222 between the magnetic poles is made smaller than the cross-sectional area of the magnetic poles of the magnetic pole teeth 223, most of the magnetic flux emitted from the rotor 21 passes through the magnetic pole teeth. Since the magnetic poles of the stator magnetic pole teeth 223 are short-circuited, the stator magnetic pole teeth 2
Attraction and repulsion of the 23 magnetic poles are reduced, and cogging torque is greatly reduced. The inner yoke 222 that short-circuits the adjacent magnetic poles of the stator magnetic pole teeth 223 preferably has the thinnest center portion between the magnetic poles. The cross-sectional area of the thinnest part at the center is the magnetic pole tooth 223.
Is preferably smaller than the cross-sectional area. Preferably magnetic pole teeth 2
It is preferable that the value be 1/3 or less of 23. Further, it is more preferable that the taper is provided from the magnetic pole toward the thinned portion at the center. When the taper is provided, the thickness of the inner yoke gradually decreases from the portion of the magnetic pole teeth 223 to the thinner portion at the center, so that the attraction and repulsion by the permanent magnet 212 become smaller. When the angle opened to the magnetic pole teeth 223 on both sides of the tapered portion is called “tooth angle”, the angle of the tooth is 140 °.
With the following taper, the cogging torque becomes extremely small.

A stator coil 225 is wound around the magnetic pole teeth 223 extending in the radial direction, and an electromotive force is generated in the stator coil 225 by an alternating magnetic field in the magnetic pole teeth. The stator coil 225 wound around each magnetic pole tooth 223 is preferably connected in series. The wire diameter of the stator coil 225 is preferably 0.1 to 0.2 mm, but it is preferable to use a coil having a large diameter in order to minimize the resistance of the stator coil 225. On the other hand, it is preferable to increase the number of turns of the stator coil 225 as much as possible in order to increase the electromotive force. At the same time, due to the requirement that the total thickness be within 2.1 mm, it is necessary that the total height including the thickness t3 shown in FIG. 8, ie, the thickness of the stator coil 225, be within 2.1 mm. . Stator coil 2 allowed on one side of stator 22
The height of 25 is (t3-t1) / 2 (mm). Here, assuming that t3 is 2.1 mm, (2-t1) / 2 (m
m). Since the number of turns of the stator coil 225 that can be wound to this thickness is determined by the coil diameter, the magnetic pole of the stator 22 preferably has a smaller thickness t1 from this aspect.

The stator 22 shown in a plan view in FIG. 9B is provided with two notches 226 and 226 '. When the input / output terminal 17 and the card contact terminal 16 are provided as in the diskette 1 shown in FIG. . Stator yoke 221
Is provided with a notch, the number of the magnetic pole teeth 223 of the stator 22 is reduced because there is no longer any part that should be in the notch 226, 226 '. However, the remaining magnetic pole teeth 223 are provided at substantially equal intervals so as to be able to face the magnetic poles of the rotor permanent magnet 212 at the same time. If there are notched stator magnetic pole teeth 223, the number is at least one pole, usually two to three poles.

In order to support the permanent magnet generator 2 of the present invention on the plastic case in the diskette, for example, the back plate 12 of the plastic case cover is made using a slightly thicker plate, and is shown in FIGS. As described above, the housing 23 made of the cup-shaped magnetic shield plate of the generator 2 can be fixed with screws. However, when the boss 211 of the rotor 21 of the generator 2 and the drive shaft of the floppy disk drive are slightly eccentric, the generator 2 needs to be displaced in the diskette 1 following the drive shaft. The generator 2 preferably has a structure in which the diskette 1 is supported by a leaf spring 31 as shown in FIG. In FIG. 11, four leaf springs 31 are supported by stop pins 32 provided on the inner surface of the back plate in the diskette, and the entire generator is supported by the elasticity of the leaf springs 31. By using such a structure, even if the generator 2 is eccentric with respect to the drive shaft, the generator 2 can be stopped according to the drive shaft.

One example of the bearing structure between the rotor 21 and the stator 22 of the generator is shown in FIGS. In this case, a shaft 232 for supporting the rotor is provided at the center of the generator housing 23, and can be rotated with respect to the shaft 232 by an oil-impregnated bearing 213 attached to the stator boss 211. . FIG. 12 shows another bearing structure in which a bearing 233 is mounted in the center of the generator housing, and a shaft 214 attached to the rotor boss is used as the bearing 23.
It is supported by 3. As another bearing structure, there is a permanent magnet generator 2 of the present invention shown in plan views in FIGS. Structures other than the bearing portion are the same as those described above, and thus description thereof will be omitted. In FIG. 13, three or six roller bearings or sliding bearings 25 are embedded in the opposing portion between the rotor and the stator. FIG. 14 shows a lubricating layer 2 having a low coefficient of friction on the opposing portion between the rotor and the stator.
6 is used as a bearing.

In the above-described embodiment, the magnetic pole teeth of the stator have been described by way of example in the form of extending radially from the stator magnetic poles.
The shape of the magnetic pole teeth is not limited to those extending radially, but may be extended outward in a plane. For example, the magnetic pole teeth located outside on the circumference may be folded in the middle and arranged in parallel. Even in such an embodiment, as described above, the dimensional relationship and material of the permanent magnet revealed by the present invention,
The number of magnetic poles, the configuration of the back yoke, the inner yoke, and the like can be implemented in common.

[0072]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The permanent magnet generator according to the present invention will be described in more detail by the following experiments, and its operating conditions will be clarified.

Experiment 1 For a permanent magnet type generator manufactured based on the design conditions shown in Table 1, the permanent magnet pole and the stator pole of the rotor were 12
Changed to ~ 24 poles. At the same time, the thickness of the stator magnetic pole in the rotation axis direction was changed from 0.5 to 1.6 mm.

[0074]

[Table 1]

FIG. 16 is a graph showing the amount of magnetic flux per pole of the permanent magnet type generator manufactured as described above, with the number of poles being varied from 12 to 24 poles and the thickness of the stator magnetic pole as a parameter. It is. Regardless of the thickness of any stator magnetic pole teeth, reducing the number of poles increases the amount of magnetic flux per pole, and increasing the number of poles decreases the amount of magnetic flux per pole. In the place where the number of poles is small, the reason why the amount of magnetic flux is smaller in the thin 0.5 mm graph than in the other graphs is probably because the magnetic pole teeth are saturated. Where the number of magnetic poles is large, the thinner the magnetic poles, the larger the amount of magnetic flux is obtained.

FIG. 17 shows the result of measuring the relative output voltage of this generator with the number of turns of the coil being constant, with the output voltage at 20 poles and a stator thickness of 1.0 mm being 100%. Things. FIG. 18 shows the result of calculating the relative output voltage by changing the number of turns of the coil. Also in FIG. 18, the stator thickness is 1.0 mm with 20 poles.
The output voltage at the time of is shown as 100%. The number of turns of this coil is 2 as described in the description of FIG.
Since the space excluding the thickness t1 of the pole teeth of the stator at the thickness of mm is (2-t1) / 2 (mm) on one side, this space is multiplied by a parameter obtained by comparison. That is, the product of the relative output voltage of FIG. 17 multiplied by the number of turns of the coil is the output voltage of the generator when the number of turns of the coil shown in FIG. 18 is changed. Therefore, t1 = 1.0 mm
Since the winding space at the time of (（) is 、 (mm), the ratio with respect to the reference at the time of the thickness t1 of the magnetic flux teeth is (2-t1) / 1 = (2-t1). FIG. 18 shows a result obtained by multiplying by using as a parameter.

As is clear from the graphs of FIGS. 17 and 18, the thickness of the magnetic pole teeth is 0.5 mm, 0.7 mm, and 1.0 mm.
And a large output is obtained, and the number of poles is preferably 16 to 20.

Experiment 2 A permanent magnet generator was manufactured in the same manner as in Experiment 1, except that a sintered NdFeB permanent anisotropic permanent magnet was used as the rotor permanent magnet. 19, 20, and 21 show the relative output voltage when the number of turns of the coil is changed and the relative output voltage when the number of turns of the coil is fixed. FIGS. 20 and 21 show a sintered NdFeB radially anisotropic permanent magnet with 20 poles and a stator thickness of 1.0 mm.
Is a relative output voltage when the output voltage is 100%.

Since the BH curve cannot be measured because it is a polar anisotropic permanent magnet, it is not shown. However, as is apparent from FIG. 19, since the amount of magnetic flux is greatly improved as compared with FIG. It can be seen that the magnetic properties are improved as compared with the anisotropy. When the thickness of the magnetic pole teeth is 0.5 mm, the magnetic pole teeth are saturated as in FIG. However, in the case of 0.7 to 1.6 mm, 10
It is rising by about%. Output voltage is 0.5m thickness of magnetic pole teeth
m, 0.7 mm, and 1.0 mm, and it turns out that it increases with 16 to 24 poles.

Experiment 3 A permanent magnet generator was manufactured in the same manner as in Experiment 1 except that a bonded permanent magnet of NdFeB was used as the rotor permanent magnet, and the amount of magnetic flux per pole and the number of turns of the coil were changed in the same manner as in Experiment 1. FIG. 22, FIG. 23, and FIG. 24 show the relative output voltage when the number of turns of the coil is fixed and the relative output voltage when the number of turns of the coil is fixed, respectively. 23 and 24 show the relative output voltage when the output voltage of a 20-pole stator with a stator thickness of 1.0 mm is 100% using a sintered NdFeB radially anisotropic permanent magnet.

The BH curve of this bonded permanent magnet is shown in FIG.
5, the residual magnetic flux density is about 0.75 T, which is 60% of the radial anisotropy of sintering. The magnetic flux amount per pole shown in FIG. 22 is about 60% of that in FIG. Even when the thickness of the magnetic pole teeth is 0.5 mm, the saturation of the magnetic pole teeth does not occur, so that the amount of magnetic flux when the number of poles is 12 is almost the same as when the thickness of the magnetic pole teeth is 1.0 mm and 0.7 mm. .

As shown in FIG. 23, the thickness of the magnetic pole teeth is 0.5
mm, the number of turns of the coil can be increased, so that the decrease in the relative output voltage as compared with Experiments 1 and 2 is not so large. Thus, it can be seen that even with a bonded magnet, considerable output can be obtained by reducing the thickness of the magnetic pole teeth. It is extremely advantageous in practice to be able to use a bonded magnet that is lightweight and easy to process.

Experiment 4 Based on the design conditions shown in Experiment 1, the sintered NdFeB radial anisotropic permanent magnet used in Experiment 1 and the sintered NdFeB polar anisotropic permanent magnet used in Experiment 2 were used. ,
Further, two permanent magnet power generators were produced under the conditions shown in Table 2 below.

[0084]

[Table 2]

The inner yoke connecting the adjacent magnetic poles of the stator magnetic pole teeth of these permanent magnet type generators has the thinnest central portion between the magnetic poles as shown in FIG. 10B. The thickness of the portion (the thickness in the radial direction) was set to 0.5 mm, and tapered from the thinnest portion toward the magnetic pole teeth at both ends. The cogging torque was measured by changing the angle of the teeth opened toward both magnetic pole teeth of the tapered portion from 80 to 180 ° (the peak-to-peak torque, that is, the sum of the attraction and repulsion torques). 25 shows the case where a radially anisotropic permanent magnet of sintered NdFeB is used, and FIG. 26 shows the case where a polar anisotropic permanent magnet of sintered NdFeB is used. As is clear from these graphs, the cogging torque is small in any case when the angle of the teeth is 140 ° or less. Those using a radial anisotropic permanent magnet have a small cogging torque even when the tooth angle is 180 °. In the case of using the polar anisotropic permanent magnet, the cogging torque sharply increases from around 140 ° with the tooth angle increased. This is probably because the polar anisotropic permanent magnet has an extremely strong orientation in the magnetic pole portion and the magnetic force is improved. It is said that there is no problem if the driving torque of the 3.5 "floppy disk drive is 2.5 Nmm or less. Therefore, there is no problem at any angle with the use of the radial anisotropic permanent magnet. A magnet using an anisotropic permanent magnet can be used up to a tooth angle of about 160 °, but is preferably 140 ° or less.

Experiment 5 Table 3 shows ideal design conditions of the permanent magnet generator of the present invention based on the above experiment results. Table 4 shows a comparison between the target characteristics and the output of the generator manufactured according to the design conditions. FIG. 27 shows the output waveform.

[0087]

[Table 3]

[0088]

[Table 4]

Experiment 6 A generator prepared according to the design conditions shown in Table 3 was 0.1 m
A cup-shaped shield plate housing made of a cold-rolled steel plate with a thickness of m is assembled on a 3.5 "diskette, and a 0.1 mm-thick permalloy plate is placed on the back of the plastic case cover opposite to the housing. A shielded version was made: a generator with a 0.1 mm thick cold rolled steel housing and one with a 0.1 mm thick permalloy plate.

The leakage magnetic field in the memory card space in the diskette is 10 Gauss or less, which is less than 2% as compared with 500 Gauss without the shield case. The leakage magnetic field has been reduced to a level that does not suffer from this.

FIG. 28 is a graph showing the leakage magnetic field in which the distance from the side surface of the diskette is plotted on the horizontal axis and the leakage magnetic field strength is plotted on the vertical axis. As is apparent from this figure, since the leakage magnetic field is reduced to 10 gauss or less immediately beside the diskette, the leakage magnetic field is reduced to a level at which no problem occurs even when the floppy disk and the diskette are arranged.

[0092]

As described in detail above, the present invention provides a generally flat permanent magnet generator which can be incorporated into a 3.5 "diskette. Notches are provided to avoid the problematic input / output terminals and card contact terminals, and the required size of output is obtained.

Further, since a back yoke capable of reducing the magnetic resistance in the stator yoke is provided, a sufficient output is obtained. Moreover, the generator was easy to assemble and manufacture.

Further, the cogging torque could be reduced, and even if the motor was rotated with a small driving torque, the rotation was smooth and an output waveform with little distortion was obtained.

The diskette having the permanent magnet generator according to the present invention can absorb the eccentricity between the boss and the drive shaft, and has almost no magnetic leakage. However, it can be handled with other floppy disks without any adverse effects.

[Brief description of the drawings]

FIG. 1 is a diskette having a permanent magnet generator according to the present invention, wherein (a) is a plan view (bottom view) of the diskette;
(B) is a 1B-1B sectional view of (a), and (c) is a partially enlarged view of (b).

FIG. 2 is a perspective view showing a diskette having the permanent magnet generator according to the present invention, showing a state where a cover of the diskette is opened.

FIG. 3 is an exploded perspective view of a diskette having the permanent magnet type generator according to the present invention, showing the diskette and the permanent magnet type generator.

FIG. 4 is an exploded perspective view of the permanent magnet generator shown in FIG.

FIG. 5 is an exploded perspective view showing an enlarged stator portion of the permanent magnet generator.

FIG. 6 is a perspective view of a permanent magnet of a rotor used in the permanent magnet generator of the present invention.

7A is a plan view of a permanent magnet of a rotor having an easy axis of magnetization in a radial direction (radial anisotropy), FIG.
(B) is a plan view of a permanent magnet of a rotor having an easy axis of magnetization in a direction connecting adjacent different poles on its circumferential surface (polar anisotropy).

8 is a sectional view taken along line 8-8 in FIG. 2, showing a relationship between the thickness of the stator magnetic pole teeth in the rotation axis direction and the length of the rotor permanent magnet in the rotation axis direction.

FIG. 9A is a plan view of a circular plate-shaped stator,
(B) is a top view of the stator with a notch.

FIG. 10 is a partially enlarged view of a stator, in which (a) shows a closed slot and (b) shows an angle of a tooth of a yoke connecting an adjacent magnetic pole at a tip of a magnetic pole tooth. FIG.

FIG. 11 is a plan view showing a state where a cover of a diskette having the permanent magnet type generator of the present invention is removed, and shows a state where the permanent magnet type generator is supported by a spring in the diskette.

FIG. 12 is an exploded perspective view showing one embodiment of a rotor bearing structure.

FIG. 13 is a plan view of a permanent magnet generator according to the present invention having a sliding bearing at a portion where a permanent magnet rotor and a stator face each other.

FIG. 14 is a plan view of a permanent magnet generator according to the present invention having a layer having a small friction coefficient as a bearing at a portion where a permanent magnet rotor and a stator face each other.

FIG. 15 shows a permanent magnet (sintered NdF) used in the present invention.
BH curve characteristic diagram of eB and NdFeB bonded magnet)
The permeance coefficient is put on top of it.

FIG. 16 shows the amount of magnetic flux per pole when the number of poles is changed in the permanent magnet generator of the present invention using a radially anisotropic permanent magnet of sintered NdFeB as the rotor permanent magnet. It is a graph which shows thickness as a parameter.

FIG. 17 is a graph showing the relative output voltage when the number of poles is changed with the output voltage when the number of poles is changed assuming that the output voltage when the stator is 20 mm and the stator thickness is 1.0 mm is 100%. It is a graph shown as a parameter (assuming the number of turns of the coil per stator magnetic pole is the same).

FIG. 18 is a graph showing the relative output voltage when the number of poles is changed with the output voltage when the number of poles is changed assuming that the output voltage when the stator is 20 mm and the stator thickness is 1.0 mm is 100%. It is a graph shown as a parameter (it changes the number of coil turns per stator magnetic pole according to stator space).

FIG. 19 shows the amount of magnetic flux per pole when the number of poles is changed in the permanent magnet generator of the present invention using a sintered NdFeB polar anisotropic permanent magnet as the rotor permanent magnet. It is a graph which shows thickness as a parameter.

20 is a graph showing the relative output voltage when the number of poles is changed using the same generator as that shown in FIG. 19, and using the thickness of the stator as a parameter (the number of turns of the coil per stator magnetic pole is adjusted to the stator space). FIG. 11 is a graph showing the output voltage when the stator is 1.0 mm thick with 20 poles using a radially anisotropic permanent magnet of sintered NdFeB, with the output voltage being 100%.

FIG. 21 is a graph showing the relative output voltage when the number of poles is changed using the same generator as in FIG. 19 and the thickness of the stator as a parameter (assuming the same number of turns of the coil per one magnetic pole of the stator); It is a graph which shows the output voltage at the time of a stator thickness of 1.0 mm and 20 poles using a radially anisotropic permanent magnet of NdFeB as 100%.

FIG. 22 shows the amount of magnetic flux per pole when the number of poles is changed, using the thickness of the stator as a parameter, in the permanent magnet generator of the present invention using a bonded permanent magnet of NdFeB as the rotor permanent magnet. It is a graph shown.

FIG. 23 is a graph showing the relative output voltage when the number of poles is changed using the same generator as in FIG. 22 and using the thickness of the stator as a parameter (the number of turns of the coil per stator magnetic pole is adjusted to the stator space). FIG. 11 is a graph showing the output voltage when the stator is 1.0 mm thick with 20 poles using a radially anisotropic permanent magnet of sintered NdFeB, with the output voltage being 100%.

FIG. 24 is a graph showing the relative output voltage when the number of poles is changed using the same generator as in FIG. 22 and the thickness of the stator as a parameter (assuming the same number of coil turns per stator magnetic pole); It is a graph which shows the output voltage at the time of a stator thickness of 1.0 mm and 20 poles using a radially anisotropic permanent magnet of NdFeB as 100%.

FIG. 25 is a graph showing the cogging torque with respect to the angle of the teeth of the inner yoke in the permanent magnet generator of the present invention using the sintered NdFeB radially anisotropic permanent magnet.

FIG. 26 is a graph showing the cogging torque with respect to the angle of the teeth of the inner yoke in the permanent magnet generator of the present invention using a sintered NdFeB polar anisotropic permanent magnet.

FIG. 27 is a diagram showing an output waveform of the permanent magnet generator of the present invention.

FIG. 28 is a graph showing the strength of the leakage magnetic field with respect to the distance from the side surface of the diskette having the permanent magnet generator of the present invention, as compared with the case without the magnetic shield.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diskette 11 Front plate 12 Back plate 13 Opening 14 Cover 15 (Memory card) space 16 Card contact terminal 17 Input / output terminal 18 CPU 19 Stabilized power supply circuit 2 (Permanent magnet type) Generator 21 Rotor 211 Boss 212 Permanent magnet 213 Oil-impregnated bearing 214 Shaft 22 Stator 221 Stator yoke 222 Inner yoke 223 Magnetic pole teeth 224, 224 'Back yoke 225 Coil 226, 226' Notch 23 Housing 231 Screw hole 232 Shaft 233 Bearing 25 Roller bearing or sliding bearing 26 Lubricity A certain layer 31 Leaf spring 32 Stop pin

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiko Takahashi 5200 Sankajiri, Kumagaya-shi, Saitama Hitachi Metals, Ltd. Inside Magnetic Materials Research Laboratories (72) Inventor Masahiro Mita 5200 Sankajiri, Kumagaya-shi, Saitama Hitachi Metals Materials Research Laboratory

Claims (35)

[Claims] (1) An annular permanent magnet that can rotate with a boss, the permanent magnet has a plurality of rotor magnetic poles arranged on a circumferential surface, and these magnetic poles are different from each other in a circumferential direction. (2) a stator having a plurality of magnetic pole teeth made of a soft magnetic material, wherein each magnetic pole tooth of the stator has (I ) Having at one end thereof a stator magnetic pole which can be opposed to each of the rotor magnetic poles provided on the circumferential surface via a magnetic air gap, and (II) extending planarly outwardly from the stator magnetic pole. And (III) the end opposite to the stator magnetic pole is connected to the opposite end of the adjacent magnetic pole tooth by a back yoke, and And the stator are formed in a flat plate shape as a whole, Permanent magnet generator for putting in a diskette, wherein a thickness of the rotation axis direction of the magnetic poles is smaller than the rotation axis direction of the thickness of the permanent magnet. 2. The magnetic poles of the permanent magnet of the rotor on the circumferential surface are arranged at substantially equal angular intervals, the number of poles is 12 to 24, and the magnetic pole teeth of the stator. 2. The permanent magnet generator according to claim 1, wherein said magnetic poles are provided so as to be able to face said magnetic poles of said rotor. 3. The permanent magnet generator according to claim 1, wherein said back yoke has an annular shape. 4. The magnetic poles of the permanent magnet of the rotor on the circumferential surface are arranged at substantially equal angular intervals, the number of poles is 12 to 24, and the magnetic pole teeth of the stator are provided. 2. The permanent magnet generator according to claim 1, wherein said magnetic poles are provided so as to be able to face each magnetic pole except at least one of the rotor magnetic poles. . 5. The magnetic pole teeth of the stator of the permanent magnet generator have (I) a stator magnetic pole at one end thereof, and the stator magnetic poles are at least one of the rotor magnetic poles except for at least one magnetic pole. And at substantially equal angular intervals on the circumference except for the portion facing the at least one pole, and (II) a plane outward from the stator poles. (III) a back made of a soft magnetic material between the poles of the magnetic pole teeth having stator magnetic poles provided at substantially equal angular intervals and opposite ends of the magnetic pole teeth. 2. The permanent magnet generator according to claim 1, wherein the permanent magnet generator is connected by a yoke. 6. The rotor according to claim 1, wherein the thickness of the magnetic poles of the stator magnetic pole teeth in the direction of the rotation axis is equal to or greater than the thickness saturated by the magnetic flux emitted from the permanent magnet of the rotor. A permanent magnet generator to be placed in the described diskette. 7. The permanent magnet generator according to claim 6, wherein the length of the permanent magnet of the rotor in the direction of the rotation axis is 2.0 mm or less. 8. The rotor according to claim 1, wherein the permanent magnet of the rotor has an axis of easy magnetization in a radial direction thereof.
A permanent magnet generator for placing in any of the diskettes described. 9. The permanent magnet of the rotor has an easy axis of magnetization in a direction connecting adjacent magnetic poles of different polarities on the circumference thereof. Permanent magnet generator for putting in a diskette. 10. The rotor permanent magnet is made of sintered Nd.
10. The magnet according to claim 8, wherein the magnet is an FeB magnet.
A permanent magnet generator to be placed in the described diskette. 11. The permanent magnet generator according to claim 1, wherein the permanent magnet of the rotor is made of NdFeB magnet powder hardened with a binder. . 12. The stator according to claim 1, wherein adjacent stator magnetic poles facing the permanent magnet at the tip of the magnetic pole teeth of the stator are connected to each other by an inner yoke. Permanent magnet generator to put in diskette. 13. The inner yoke connecting the adjacent stator magnetic poles at the tip of the magnetic pole teeth, the central portion between the adjacent stator magnetic poles is the thinnest. A permanent magnet generator to be placed in the described diskette. 14. The inner yoke connecting adjacent stator poles at the tip of the pole teeth, the inner yoke has a cross-sectional area at the center between the adjacent stator poles smaller than the cross-sectional area of the pole teeth. 13. A permanent magnet generator for placing in a diskette according to claim 12. 15. A diskette having a diskette case and a permanent magnet type generator provided in the diskette case, wherein the permanent magnet type generator comprises: (1) an annular permanent magnet which can rotate together with a boss. The permanent magnet has a plurality of rotor magnetic poles arranged on a circumferential surface, and these magnetic poles have different polarities in a circumferential direction. A rotor and (2) a plurality of soft magnetic materials And (I) each of the magnetic pole teeth of the stator may face each of the rotor magnetic poles provided on the circumferential surface via a magnetic gap. (II) extending in a plane outwardly from the stator poles and having a stator coil wound thereon, and (III) an end opposite to the stator poles. Section is opposite to the opposite end of the adjacent pole tooth. The rotor and the stator are configured as a plate as a whole, and the thickness of the stator magnetic poles in the rotation axis direction is greater than the thickness of the permanent magnets in the rotation axis direction. A diskette incorporating a permanent magnet generator characterized by its small size. 16. The magnetic poles of the permanent magnet of the rotor on the circumferential surface are arranged at substantially equal angular intervals, the number of poles is 12 to 24, and the magnetic pole teeth of the stator are provided. The diskette according to claim 15, wherein the magnetic poles are provided so as to be able to face the magnetic poles of the rotor. 17. The diskette according to claim 15, wherein said back yoke has an annular shape. 18. The magnetic poles of a permanent magnet of a rotor on a circumferential surface are arranged at substantially equal angular intervals, the number of poles is 12 to 24, and the magnetic pole teeth of a stator are provided. 16. The diskette according to claim 15, wherein each of the magnetic poles is provided so as to be able to face each magnetic pole except at least one of the rotor magnetic poles. 19. The magnetic pole teeth of the stator of the permanent magnet generator have (I) a stator magnetic pole at one end thereof, and the stator magnetic poles are at least one of the rotor magnetic poles except for at least one magnetic pole. And at substantially equal angular intervals on the circumference except for the portion facing the at least one pole, and (II) a plane outward from the stator poles. (III) a back made of a soft magnetic material between the magnetic pole teeth of the magnetic pole teeth having stator magnetic poles provided at substantially equal angular intervals and opposite ends thereof. The diskette incorporating the permanent magnet generator according to claim 15, wherein the diskette is connected by a yoke. 20. The disk drive according to claim 18, wherein one of an input / output terminal of a diskette, a card contact terminal, and a memory card insertion space is provided between stator magnetic pole teeth which are not connected to each other by a back yoke. Alternatively, a diskette incorporating the permanent magnet generator according to item 19. 21. The stator according to claim 15, wherein the thickness of the magnetic poles of the stator magnetic pole teeth in the direction of the rotation axis is greater than a thickness saturated by magnetic flux emitted from the permanent magnet of the rotor.
A diskette incorporating the permanent magnet generator described. 22. The permanent magnet of the rotor has a length in the rotation axis direction of 2.0 mm or less.
A diskette incorporating the permanent magnet generator described. 23. The rotor according to claim 15, wherein the permanent magnet of the rotor has an axis of easy magnetization in a radial direction thereof.
23. A diskette incorporating the permanent magnet generator according to any one of to 22. 24. The permanent magnet of the rotor according to claim 15, wherein the permanent magnet has an axis of easy magnetization in a direction connecting adjacent magnetic poles of different polarities on the circumference thereof. Diskette incorporating a permanent magnet generator. 25. The permanent magnet of the rotor is made of sintered Nd.
25. A diskette incorporating the permanent magnet generator according to claim 23, wherein the diskette is an FeB magnet. 26. A diskette incorporating a permanent magnet generator according to claim 15, wherein the permanent magnet of the rotor is formed by hardening NdFeB magnet powder with a binder. 27. The permanent magnet according to claim 15, wherein adjacent stator magnetic poles facing the permanent magnet at the tip of the magnetic pole teeth of the stator are connected to each other by an inner yoke. Diskette with built-in generator. 28. The inner yoke connecting adjacent stator magnetic poles at the tip of the magnetic pole teeth, the central portion between the adjacent stator magnetic poles being the thinnest. A diskette incorporating the permanent magnet generator described. 29. The inner yoke connecting adjacent stator poles at the tip of the pole teeth, the inner yoke having a cross-sectional area at the center between the adjacent stator poles smaller than the cross-sectional area of the pole teeth. 28. A diskette incorporating the permanent magnet generator according to claim 27. 30. A diskette incorporating a permanent magnet type generator according to claim 15, wherein a memory card insertion space is provided in said diskette case. 31. The memory card insertion space and the permanent magnet generator at least partially overlap,
The diskette according to claim 30, wherein at least a part of the boundary wall is a magnetic shield plate. 32. The diskette incorporating a permanent magnet generator according to claim 31, wherein the boundary wall is a housing of a permanent magnet generator. 33. The diskette case according to claim 15, wherein a holding mechanism capable of absorbing eccentricity of the permanent magnet generator with respect to the diskette case is provided in the diskette case. A diskette incorporating a permanent magnet generator. 34. A diskette incorporating a permanent magnet generator according to any one of claims 15 to 33, wherein a boss of the permanent magnet generator can engage a drive shaft of a disk drive. 35. A diskette incorporating a permanent magnet generator according to claim 15, wherein said diskette is structured to be attached to a 3.5 ″ floppy disk drive.