JPS61161944A - Permanent magnet for flat motor - Google Patents

Abstract

PURPOSE:To reduce the variation in the torque by dividing a permanent magnet into plural magnets, and forming the splitting line from the center of the armature nonradially, thereby gradually varying a magnetic flux distribution operating on an armature coil. CONSTITUTION:In a flat motor in which a flat armature 2 and a permanent magnet 4 are opposed through an axial air gap, the magnet 4 is divided into a plurality. The radial end 14a of the split portion is formed in nonparallel state with respect to a normal line from the rotating center of the armature 2. Parallel grooves 15 are formed on the divided portion. Thus, when the armature 2 passes an electric position, armature coils 34 are not abruptly telescoped in the magnetic distribution of the magnet 4, the variation in the torque decreases to smoothly rotate it.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field 1 The present invention relates to a permanent magnet for a flat motor, and in particular, it prevents sudden changes in magnetic flux distribution that occur when an armature passes through an electrical position, and minimizes rotational torque fluctuations. Smooth rotation can be obtained, and the groove of each permanent magnet can be effectively used.
This invention relates to a permanent magnet for flat motors that is easy to assemble.

PRIOR ART Recently, small motors have been widely used in small audio equipment such as toys and portable stereo cassette tape recorders, but as these types of audio equipment are increasingly required to be smaller and have higher sound quality. As a result, ultra-thin and high-performance compact motors are now required.

However, in conventional flat type motors, the dividing lines of the plurality of field permanent magnets are formed radially, parallel to the normal line from the rotation center of the armature. (Refer to page 59 of the 3rd edition of "Mechatronics Guide to DC Servo Motors" published by the publisher) Therefore, when the armature passes through the electrical position, it is shocked by the sudden change in magnetic flux distribution caused by each permanent magnet piece. However, there is a drawback that torque fluctuation occurs, which tends to cause uneven rotation.

Purpose The present invention has been made in order to eliminate the drawbacks of the prior art described above, and its purpose is to improve the radial direction of a field permanent magnet piece divided into a plurality of pieces in a flat type motor. By forming the dividing lines forming the ends in a non-parallel state to the normal line from the rotation center of the armature, that is, in a non-radial manner, each electric To provide a flat type motor in which a child coil gradually moves into and out of the magnetic flux distribution on a permanent magnet side without abruptly moving in and out, and has extremely little torque fluctuation and smooth rotation. Another purpose is to make the permanent magnet pieces into a shape that creates parallel grooves of the same width between each permanent magnet piece to make effective use of the grooves, and to manufacture and use the permanent magnet pieces. The objective is to facilitate the assembly of flat type motors.

In short, in the present invention, the armature has a flat disk-like structure, and a field permanent magnet is disposed on an axial side surface of the armature to face the armature through an air gap. In the flat type motor, the permanent magnet is divided into a plurality of parts,
A dividing line forming a radial end of each divided permanent magnet piece is formed in a non-parallel state with respect to a normal line from the rotation center of the armature.

As shown in FIGS. 1 and 2, the flat motor 1 according to the present invention has an armature 2 having a flat disk-like structure, and an air field formed on the axial side surface of the armature through an air gap 3. The magnetic field permanent magnet 4, the brush mounting device 5, the motor case 6, 7, and the armature are arranged so as to face the armature 2. The main parts include a coil core 9, a flat commutator 10, a rotating shaft 11, a thrust washer 12, and a mounting plate 13 made of a magnetic material.

First, the field permanent magnet 4 for the flat motor 1 will be explained with reference to FIGS. 1 to 6. The permanent magnet 4 includes a plurality of
For example, it is divided into two, and the dividing line 11 forming the radial end 14a of each divided permanent magnet piece 14 is in a non-parallel state with respect to the normal 12 from the rotation center 0 of the armature 2,
That is, they are formed non-radially. In this way, the dividing lines 1 of the two permanent magnet pieces 14 are, for example, parallel to each other, and parallel grooves 15 of the same width are formed between each permanent magnet piece 14.

Furthermore, the number of permanent magnet pieces 14 is not limited to two; for example, as shown in FIG. 5, the permanent magnet pieces 14 of the permanent magnet 4 can of course be divided into four. Even in this case, the dividing line 11 forming the end 14a of each permanent magnet piece 14 is the normal line I! from the rotation center O of the armature 2! 2, that is, the dividing line 11 is formed non-radially from the rotation center O of the armature 2.

Similar to the permanent magnet 4 shown in FIG. 3, parallel grooves 15 are formed vertically and horizontally. Therefore, no matter how many pieces the permanent magnet 4 is divided into, the dividing line lI of each permanent magnet piece 14 is the same as the armature 2.
It is always formed non-radially with respect to the rotation center O.

The reason why the dividing lines of each permanent magnet piece 14 of the permanent magnet 4 are formed in a non-radial manner is to prevent the abrupt magnetic flux distribution when the armature 2 passes through the electrical position and enters the magnetic field of the permanent magnet piece 14. This is to prevent variations in rotational torque, thereby reducing fluctuations in rotational torque.

Next, the brush mounting device 5 of the flat motor 1 will be explained with reference to FIGS. 1 to 6. In the brush mounting device, parallel grooves are formed between each divided permanent magnet piece 4. A brush 18 having a carbon brush 19 attached to one end 18a that contacts the commutator 10 is housed in the magnet 15, and is configured to fit within the thickness of the permanent magnet 4. The brush spring 20 of the brush 18 is fixed to the motor case 7 via an insulator 24 and a washer 25 made of an insulating material through a mounting plate 13 made of a magnetic material with a screw 21 and a nut 22. Connect terminal 26 to motor case 7
It is fixed at

A lead wire 27 is connected to the terminal 26.

For installation, the plate 13 is made of iron and is formed into a disk shape, and a bearing 28 for the rotating shaft 11 is fixed to the center of the plate.
One end 11a of the rotating shaft 11 is supported by the bearing. In this way, in the brush mounting device 5 according to the present invention, the brush 18 is attached to the parallel groove 1 of the permanent magnet 4.
5, there is no need to provide a separate space for installing the brush, and as a result, the thickness of the flat motor 1 can be reduced by that amount.

It was made by sea urchin.

The flat commutator 10 is fixed to the rotating shaft 11 via an insulator 30. For example, when the armature 2 has three poles as shown in the drawing, the commutator is divided into three parts in the circumferential direction by the insulator 30. has been done. A conductive plate 31 made of, for example, a copper plate or a silver alloy plate with good conductivity is attached between the insulators. Then, the carbon brush 19 of the brush 18 is pressed against and comes into contact with the conductive plate, and slides on the surface thereof.

Next, the armature 2 of the flat motor 1 will be explained in Figs. 1 and 2.
This will be explained with reference to FIGS. 7 and 8.

The armature 2 has a plurality of armature coils 34 formed by winding a conductive wire or conductive foil 33 around an iron core 9 a predetermined number of times, and a dividing plate 35 made of a magnetic material for each armature coil 34 on a surface 34a on the permanent magnet 4 side. is attached, and the armature coil 34
A disk 36 made of a magnetic material for forming a magnetic circuit is adhered to the back surface 34b of the armature coil 34 so as to extend over each armature coil 34. The disc 36 is the commutator 10
It is fixed integrally with the insulator 30 of the rotary shaft 11, and is fixed to the rotating shaft 11 in its entirety. Note that as the magnetic material for the dividing plate 35 and the disc 36, for example, an iron plate is used. The reason why the dividing plate 35 and the disc 36 are attached to the front surface 34a and the back surface 34b of the armature coil 34 in this way is because the permanent magnet 4 and the mounting plate 13
This is to form a magnetic circuit between the armature 2 and the armature 2. Therefore, the space 38 between the disc 36 and the inner surface 6a of the motor case 6 is completely unrelated to the magnetic circuit, and the motor case 6.7 is also completely unrelated to the magnetic circuit.

The iron core 9 is formed by winding a thin plate 39 made of a magnetic material, and is designed to have a higher coercive force than a solid iron core.

Note that the conductive wire or conductive foil 33 that constitutes the armature coil 34
For example, if a conductive wire can be wound 671 turns, if the thickness of the conductive foil is 20μ, it can be wound 855 turns in the same volume, which improves the volume occupation rate compared to the conductive wire. As a result, the efficiency can be increased by 30% compared to the case of conductive wires. Therefore, in the ultra-small flat motor 1, more powerful output can be obtained by using conductive foil.

Next, the connection of the armature coils 34 will be explained with reference to FIG. 7. In the case of delta connection, the winding start S of the conductive wire or conductive foil 33 of each armature coil 34 is connected to the commutator 10 on the counterclockwise side in the figure. The winding end E is connected to the terminal 31a of the conductive plate 31 on the clockwise side. Thereafter, the commutator 10 and each armature coil 34 are electrically connected by wiring in the same manner.

Next, the iron core 9 for the armature coil 34 will be explained. 9 to 12, the method for manufacturing the iron core 9 will first be described. As shown in FIG. 9, a thin plate 39 made of a magnetic material, for example an iron plate, is wound around a core bar 40 as shown by arrow A.

In this case, one end 39a of the thin plate 39 is locked in a groove 40a formed in the core bar 40, thereby rotating the core bar 40 and winding the thin plate 39 around it. This core metal 4
For example, an iron rod with a diameter of about 1.5 cranes is used. In this way, the thin plate 39 is wound around the core bar 40 in a spiral manner, and the tenth
An iron core coil 41 having a circular cross section as shown in the figure is formed, the core metal 40 is extracted from the iron core coil, and the iron core coil is then inserted into a groove 51a having the same angle as the center angle θ corresponding to the number of poles of the armature coil 34. A first press die 51 having a circular concave surface 52a and a second press die 52 having an arcuate concave surface 52a are used to press the iron core 9 into a fan-shaped iron core 9 having a center angle equal to the center angle θ of the armature coil 34.

In reality, the first press die 51 is used as the lower press die, the second press die 52 is used as the upper press die, and the second press die 52 is placed on the first press die 51 as shown in FIG. The 11th iron core coil 41 is lowered as shown by arrow B.
As shown in the figure, the core coil 41 is compressed by both press dies 51 and 52, and the core 9 as shown in FIG. 12 can be manufactured. Note that this method of manufacturing the iron core 9 can also be performed using a narrow thin plate 39 having the same width as the iron core 9 in the finished state, but in order to manufacture this more efficiently, A thin plate 39 having a width considerably wider than the width of the thin plate 39 may be wound around the core metal 40 and pressed and formed as shown in FIG. 11, and then cut to the width required in the finished state.

When manufacturing the armature coil 34 from the iron core 9 completed in this way, a conductive wire or conductive foil 33 may be wound around the iron core 9, or the armature coil 34 wound in an air-core state may be used. The iron core 9 may be inserted into the core 9. In any case, using the iron core 9 with the thin plates 39 laminated in this way has a much stronger coercive force than using a solid iron core, and a very large rotational force can be extracted from the armature 2. I can do it.

Next, the motor cases 6 and 7 will be explained with reference to FIG. 2 and FIGS. 14 to 18. In the flat motor 1 according to the present invention, as described above, since the magnetic circuit is formed only by the permanent magnet 4, the mounting plate 13, and the armature 2, the motor case 6.7 is excluded from the magnetic circuit. Therefore, non-ferrous materials such as synthetic resin can be used for the motor case 6.7. However, if synthetic resin is used for the motor case 6.7, it will be difficult to absorb the noise generated from the flat motor l, and noise may occur in electronic devices that use weak currents. It is desirable to use a synthetic resin mixed with magnetic material powder for noise prevention, such as iron powder, for the case 6.7.

Next, the structure of the motor case 6.7 will be explained.
As shown in FIGS. 14 to 18, the motor case 7 is formed in a circular shape, and has a counterbore 7b formed in its wall surface 7a, and a small diameter portion 7d continuous with the large diameter portion 7C. , a pair of L-shaped grooves 7e bent in the circumferential direction and the axial direction are formed. The outer periphery of the mounting plate 13 is fitted into the inner surface of the small diameter portion 7d.

The motor canis 6 is formed in the same shape as the motor case 7, and its inner periphery is adapted to fit into the small diameter portion 7d of the motor case 7, and a pair of protrusions 6e are fitted into the small diameter portion 7d of the motor case 7. and are secured by engaging and twisting each other in the circumferential direction. A hole 6b is formed in the center of the motor case 6.
A bearing 53 of the rotating shaft 11 is fixed in the hole.

Function The present invention is constructed as described above, and its function will be explained below. First, the assembly of the flat motor 1 according to the present invention will be described. The outer diameter of the commutator 10 is set smaller than the width of the parallel groove 15 formed by each permanent magnet piece 14 of the permanent magnet 4. The cylindrical portion 10a is the cylindrical protrusion 36 of the disk 36.
a and are fixed to each other. On the other hand, armature coil 3
4 and the iron core 9 are combined, and the dividing plate 35 is attached to this, and in this state, the back surface 34 of the armature coil 34 is
A disc 36 is attached to b. Accordingly, the armature coil 34, the dividing plate 35, the iron core 9, the disc 36, the commutator 10, and the rotating shaft 11 are integrated and each connection is made, and the armature 2 is completed.

Then, the rotating shaft 11 is press-fitted into the disk 36 and the commutator 10, and the rotating shaft is fixed to the armature 2.

On the other hand, a mounting plate 13 is assembled to the motor case 7.
A screw 21 penetrates the motor case 7 and protrudes to the outside, and is connected to a terminal 26 by a nut 22 from the outside of the motor case 7.
is attached, and at the same time, the brush 18 is fixed to the mounting plate 13 with the screws 21 via the insulators 24 and 25. Note that if the case 7 is made of a conductive material,
It is necessary to provide an insulator (not shown) between the terminal 26 and the screw 21 and the case 7. and carbon brush 1
9 faces the commutator 10, and the carbon brush 19 is given elastic force by a brush spring 20.

When the brush 20 and the mounting plate 13 are attached to the motor case 7 in this way, each permanent magnet piece 14 of the permanent magnet 4 is then fixed to the mounting plate 13, and then the armature 2 integrated with the rotating shaft 11 is attached. When inserted from the left in FIG.
8 and is supported. Note that each permanent magnet piece 14 may be fixed to the mounting plate 13 in advance.

In this case, since the commutator 10 is flat, assembly to the carbon brush 19, which is waiting on the right side in the figure, is completed by just being lightly pressed from the side, and the commutator 10 is attached to the carbon brush 19, which is waiting on the right side in the figure. It is much easier to assemble than the previous version.

When the armature 2 is assembled to the motor case 7 in this way, the motor case 6 is attached to the rotating shaft 11 by its bearing 53.
is guided and inserted into the motor case 7. In this case, the protrusion 6 of the motor case 6
e fits into the groove 7e of the motor case 7, and
By rotating the motor case 6 in the clockwise direction in FIG. 2, the protrusion 6e and the groove 7e are brought into engagement, the motor cases 6 and 7 are fixed to each other, and the assembly of the flat motor 1 is completed. .

As described above, the assembly of the flat motor 1 according to the present invention is very simple, and the brushes 18 are included within the thickness of the permanent magnet 4.
Since there is no need to provide a separate space for accommodating the brushes, the flat motor 1 can be made very thin. For example, the motor case 6.7
The thickness of the flat motor 1 in the assembled state is 5.2
It is possible to make the motor 1 as thin as 100 m, and an ultra-thin flat motor 1 can be realized.

Next, to explain the characteristics of the flat motor 1 assembled in this way, first of all, regarding the permanent magnets 4,
While the dividing line 7!1 of each permanent magnet piece 14 is non-radial, the end 3 of each armature coil 34 of the armature 2
4C is formed radially with respect to the rotation center O of the armature 2, and is parallel to the normal line 12, so as shown in FIG. When the coil 34 rotates, the end 34C of the armature coil 34 first begins to enter the magnetic field of the permanent magnet piece 14 from the outer circumferential end 14b of the permanent magnet piece 14, and meets the parting line with the end 34c. , the armature coil 34 is attracted to the magnetic field of the permanent magnet piece 14 as the intersection point P gradually moves inward. Therefore, when the armature coil 34 passes through the electrical position, the change in magnetic flux density does not become rapid, and as a result, the fluctuating torque applied to the armature 2 is reduced, and rotational unevenness of the armature is reduced. This is explained by the permanent magnet piece 14 as shown in FIG.
The same holds true even when four are provided.

Further, as described above, in the brush mounting device 5 according to the present invention, since the brush 18 is housed within the plate thickness of the magnet 4, the thickness t of the flat motor 1 is extremely thin, for example, t = 5. However, by increasing the thickness of the permanent magnet 4 or increasing the thickness of the armature 2 to compensate for this thinning, it is possible to create a flat motor with the same thickness as the conventional motor. Needless to say, if you have one, you will be able to obtain much stronger rotational force than conventional ones. Since the brush mounting device 5 allows the flat motor 1 to be made extremely thin, it is possible to fully realize a stereo cassette tape recorder with a thickness equal to the width of the cassette tape. Accordingly, it is possible to provide a flat motor 1 that generates high output.

Next, in the armature 2 according to the present invention, dividing plates 35 made of a magnetic material are attached to the front surface 34a of the armature coil 34, and a disc 36 made of a magnetic material is attached to the back surface 34b. Therefore, a closed magnetic circuit is formed between the permanent magnet 4 and the mounting plate 13, and the armature 2, and all the magnetic flux emitted from the permanent magnet 4 and the armature 2 circulates within this magnetic circuit. By improving the precision of the air gap 3 between the permanent magnet 4 and the dividing plate 35, the air gap can be made very narrow, thereby making it possible to obtain a strong rotational force. In addition, since the space 38 between the armature 2 and the case 7 has no relation to the magnetic circuit, there is no need to strictly control the dimensions of this space, and the conventional ferrite magnet that uses this space as an air gap is no longer required. It can generate much more powerful rotational force than a motor.

Therefore, in the flat type motor l according to the present invention, an inexpensive ferrite permanent magnet 4 is used instead of a samarium cobalt magnet or a comparable strong permanent magnet used in conventional motors of this type. It is possible to obtain the same high output using these extremely expensive permanent magnets.

Also, since the motor case 6.7 is no longer used in the magnetic circuit, the motor case may of course be made of iron, but it can also be made of any material other than iron, such as various synthetic resins. You can also freely change the color and design. Furthermore, by mixing magnetic material powder for noise prevention, such as iron powder, into the synthetic resin, it is possible to completely prevent defects such as noise generation from the flat motor 1 causing radio wave interference.

Effects Since the present invention is constructed and operates as described above, the division line forming the radial end of the field permanent magnet piece divided into a plurality of pieces in the flat type motor is controlled by the rotation of the armature. Since it is formed so that it is non-parallel to the normal line from the center, that is, it is formed non-radially, when the armature passes through the electrical position, each armature coil is in the magnetic flux distribution on the permanent magnet side. Because the armature does not move in and out suddenly (and moves gradually), the armature torque fluctuation is extremely small.
This has the effect of providing a flat motor with smooth rotation. In addition, since the permanent magnet is shaped so that parallel grooves of the same width are formed between each permanent magnet piece, the grooves can be used effectively. This has the effect of making assembly easier.

[Brief explanation of drawings]

The drawings relate to embodiments of the present invention; FIG. 1 is a partial vertical sectional view of a flat motor in a completed state, FIG. 2 is an exploded perspective view of the flat motor, and FIG. 3 is a permanent magnet for a field divided into two parts. A front view showing the mutual relationship between the magnet and the armature in the rotating state, Figure 4 is a plan view of the one shown in Figure 3, and Figure 5 shows the mutual relationship between the permanent magnet divided into four parts and the armature in the rotating state. 6 is a plan view of the one shown in FIG. 5, FIG. 7 is a front view of the armature shown in FIG. Electron - Vertical cross-sectional view in the direction of the ■ arrow, No. 9
Figures 11 to 11 relate to a method for manufacturing an armature coil core, and Figure 9 is a perspective view showing a state in which a thin plate is wound around a core metal;
FIG. 10 is a front view showing the first stage of the pressing process of a completed iron core coil with a circular cross section, FIG. 11 is a front view showing the second stage of the pressing process, and FIG. 12 is a perspective view of the completed iron core for armature coils. FIG. 13 is a front view of the motor case 7 seen from inside, FIG. 14 is a plan view of what is shown in FIG.
5 is a longitudinal cross-sectional view of what is shown in FIG. 13, FIG. 16 is a front view of the motor case 6 seen from the inside, FIG. 17 is a plan view of what is shown in FIG. 16, and FIG. 18 is what is shown in FIG. 16. FIG. 1 is a flat motor, 2 is an armature, 3 is an air gap, 4
14 is a permanent magnet for a field; 14 is a permanent magnet piece; 14a is a radial end portion; 15 is a parallel groove; 2. is the dividing line, 12 is the normal line,
0 is the center of rotation of the armature. Patent applicant Kiyonori Fujisaki Toshio Kobayashi

Claims (1)

[Claims] 1. The armature has a flat disk-like structure, and a field permanent magnet is disposed on the axial side surface of the armature to face the armature through an air gap. In the flat type motor, the permanent magnet is divided into a plurality of parts, and the dividing line forming the radial end of each divided permanent magnet piece is non-parallel to the normal line from the rotation center of the armature. A permanent magnet for a flat motor, characterized by being formed into a shape. 2. The permanent magnet piece according to claim 1, wherein the dividing lines of the permanent magnet pieces are parallel to each other, and parallel grooves of the same width are formed in each permanent magnet piece opening. Permanent magnet for flat motors.