JPS63133858A - 2-phase brushless motor - Google Patents

Abstract

PURPOSE:To increase the volumetric ratio of a coil, by a method wherein magnetic flux, generated in a toroidal driving coil, is concentrated into toroidal inner yoke and outer yoke to arrange it within areas of a plurality of radii of curvature. CONSTITUTION:A 2-phase brushless motor 10 is equipped with a frame 12, a stator 14, fixed to the radial surface of the mount unit 12a of the frame 12, and a rotor 26. The stator 14 is equipped with a disc type stator yoke 15, extending radially, and the rotary shaft 22 of the rotor 26 is supported by both ends of the frame 12 through bearings 18, 20. First and second phase toroidal driving coils 28-30, having different radial of curvature, and a toroidal inner yokes and outer yokes 28-32, for concentrating the flux of magnetic flux, are arranged on the plane of the stator yoke 15 while arc-shaped magnetic poles 32p-38p and cut sections 52c-38c are formed. Further, toroidal magnetism interrupting members 40-44 are arranged whereby the flux density of respective phases may be increased.

Description

[Detailed Description of the Invention] [Technical Field] This invention relates to a brushless motor, and more specifically,
The present invention relates to an axial air gap type two-phase brushless motor.

With the recent progress in making various devices smaller, lighter, and higher in performance, axial air gap type flat motors have been proposed. Information equipment and OA (office automation)
Conventional flat motors, which are used as stepping motors in electronic devices, consist of a stator with many drive coils arranged on a flat surface on a stator yoke, and a rotor with a disc rotor with many magnets arranged on a flat surface. is opposed to the stator, and the drive coil is sandwiched between the magnet and the stator yoke. A flat motor used as a servo motor in FA (factory automation) equipment is well known as a print motor. This print motor has a large number of permanent magnets arranged on the plane of the stator so that N poles and SF@ poles alternate, and a disc rotor equipped with armature windings is opposed to these permanent magnets, and a commutator and brushes are connected to each other. Driven through amateur winding? 11
It has a structure that supplies flow. A common drawback of these two types of flat motors is that the presence of magnetic coils or armature windings between the rotor and stator yoke in the magnetic circuit necessarily results in a large air gap and a high magnetic reluctance. Furthermore, the target magnetic field of each coil or armature winding is dispersed, the target magnetic field area of these coils or windings becomes large, and there is a drawback that the magnetic flux density for the same magnetic pole is low. As a result, the magnetic field becomes weak and the efficiency of the motor deteriorates, making it difficult to further reduce size, weight, and improve performance. To solve this problem, it has been proposed to use a high-grade class 2 magnet for the rotor magnet, but due to the special structure of the motor, the air gap itself between the rotor and the stator yoke cannot be made small. However, the efficiency of the motor is not improved and the manufacturing cost is increased. However, because the target magnetic field of each main coil or amateur winding is dispersed, there is a large amount of magnetic leakage around the motor, especially for floppy disk drive devices that perform magnetic recording and precision 81g constants that require high-density magnetic recording. This had a huge negative impact on the equipment. In addition to the aforementioned drawbacks, print motors also have
Since the armature winding is provided on the rotor, the overall weight of the rotor increases, and the rotor inertia increases.As a result, the power rate decreases, high-speed response is not possible, and there is a lack of stability. . Furthermore, print motors have mechanical sliding and wear parts, making them unreliable and requiring periodic maintenance and inspection.They also generate sparks and noise, which places major restrictions on the environmental conditions in which they can be used. There was also a limit to the overload capacity in the high speed range due to the mechanical rectification effect. Therefore, this motor is not suitable for high-speed rotation, cannot be used in locations with environmental conditions such as vibration, shock, and high temperature, and has the further disadvantage that the characteristics of the motor deteriorate over time.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly reliable two-phase brushless motor that is highly efficient, compact and lightweight, and capable of high performance.

Another object of the present invention is to provide a two-phase brushless motor that is highly efficient and can be made ultra-thin.

Another purpose of this invention is to reduce magnetic leakage and electromagnetic noise.
Our purpose is to provide phase brushless motors.

Another object of the present invention is to provide a low-cost two-phase brushless motor that is simple in structure, easy to assemble, and can be put to practical use in small to large capacity machines.

Another object of this invention is to reduce the inertia of the rotor, and to reduce the power density (kw/kg) and power rate (kw/kg).
An object of the present invention is to provide a two-phase brushless motor with significantly improved speed.

Another purpose of this invention is to reduce the air gap and increase the starting torque.

Excellent slewing characteristics. In particular, it is an object of the present invention to provide a two-phase brushless motor that can be used as a stepping motor or a servo motor.

Another object of this invention is to apply J′? overload-r
Nitofuri”, ? It is an object of the present invention to provide a two-phase brushless motor that is excellent in environmental friendliness such as electric shock and can be used under any lit conditions.

Another object of the present invention is to provide a low-cost, long-life motor that can be used as a general-purpose DC motor or a single-phase AC motor.
Moreover, it is an object of the present invention to provide a two-phase brushless motor that is highly efficient.

[Structure of the invention]

The brushless motor of the present invention has first and second phase toroidal 1ψ moving coils with different radii of curvature arranged concentrically on the stator, and each lψ moving coil is provided with a toroidal inner yoke and a toroidal outer yoke for magnetic flux concentration. death.

A first Aikawa magnetic pole and a second Aikawa magnetic pole are formed in a predetermined first phase relationship at the ends of the iq inner yoke and the outer yoke of the first and second phase drive aJ coils, and the rotor A first Aikawa magnetic pole and a second Aikawa magnetic pole are formed in different radii of curvature regions in the disk, and the rotor disk is attracted in a fixed direction to a part of the rotor disk or the first Aikawa magnetic pole and the second Aikawa magnetic pole of the stator. A low reluctance portion is formed, and the first and second Aikawa 6B poles of the rotor disk are connected to the first and second Aikawa magnetic poles of the toroidal inner yoke and the toroidal outer yoke, respectively. They are characterized by facing each other in a phase relationship with an air gap in between.

〔Example〕

An embodiment in which the brushless motor according to the present invention is applied to a two-phase brushless motor will be described with reference to FIGS. 1 to 3. In FIGS. 1 and 2, the two-phase brushless motor 10 has a frame 12 and a mount L of the frame 12.
A stator 14 is fixed to the radial surface of 2a.

The stator 14 includes a stator yoke 15 made of a disc-shaped material with high magnetic permeability and extending in the radial direction. A housing 16 is fixed to this stator yoke 15. Frame I
2 acts as a bearing holder - for example 1 supporting bearings 18.20 at each end of the frame 12
A rotating shaft or spindle 22 is rotatably supported by a bearing 18.20, and a rotor 26 is secured to the lower end of the rotating shaft 22 via a screw 24. On the plane J,- of the stator yoke 15, first-phase and second-phase toroidal drive coils 28.degree. 30 having different radii of curvature are arranged concentrically with the rotating shaft 22.

A toroidal inner yoke 32.34 and a toroidal outer yoke 36.38 extending in the axial direction for concentrating magnetic flux are arranged on the inner JlvPI and outer circumference of the toroidal drive coil 28.30, respectively. Inner yoke 32.
34 and the back surfaces of the outer yokes 36 and 38 are respectively fixed to the stator yoke 15 via a bonding agent (not shown) or other suitable means. On the front surfaces of the inner yokes 32, 34 and the outer yokes 36, 38, arcuate magnetic poles 32F, 34P, 36P, 38P are predetermined first. It is formed by the phase relationship of Arc-shaped magnetic pole 3
Cut portions 32G, 34G, 36G, and 38G that form low permeance portions are formed on 2P, 34P, 36F, and 38P, respectively, and these cut portions 32C, 34C, and 3
6G, 38C and arc-shaped magnetic poles 32P, 34P, 36F
, 38P are arranged symmetrically with respect to the X axis, that is, in the same phase. However, the arcuate magnetic poles 32P, 36P and cut portions 32C, 36 of the phase yoke 32.36
For C, the arcuate magnetic pole 34 of the second phase yoke 34.38
P, 38P and cut part 34C938C in electrical angle 1
The inner yoke 32.34 and the outer yoke 36.38 may be arranged so that they are out of phase by 8o degrees, that is, symmetrically with respect to the center of the motor axis.Both the inner yoke 32.34 and the outer yoke 36.38 are made of high magnetic permeability material such as soft iron or silicon steel plate. Formed from material.

Inner yoke 32.34 and outer yoke 36.3
8 has a plurality of thin slits 32a+ extending in the radial direction.
34a, 36a, and 38a are formed, respectively. This is due to the magnetic skin effect caused by the fluctuating magnetic flux when the toroidal drive coil turns on and off, and the area of high magnetic flux density that effectively contributes to electromagnetic force becomes extremely narrow, increasing magnetic resistance and reducing the total magnetic flux. This is to prevent the output torque from decreasing. These slits effectively suppress eddy currents, which are the effects of demagnetizing fields on fluctuating magnetic flux, so that the strong magnetic flux portion is distributed uniformly over a wide portion of each magnetic pole surface of the toroidal inner yoke and toroidal outer yoke of each phase. It has the effect of

The first phase outer yoke 36 and the second phase inner yoke 3
A toroidal magnetic shielding member 40 made of a conductive material such as copper or aluminum is disposed between the first and second phase stators to block magnetic leakage between the first and second phase stators. The back side of the magnetic shielding member 40 is fixed to the stator yoke 15, and its front side is preferably aligned with the magnetic pole face of the adjacent yoke 34,36. Adjacent to the outer periphery of the outer yoke 38 is a toroidal magnetic 'gl! 97 member 42 is arranged to effectively prevent magnetic leakage from the outer yoke 38 to the housing 16.

Magnetic isolation rings 44, 46 made of a conductor are arranged on the first plane of the 1st and 2nd phase toroidal drive coils 28, 30, respectively. The magnetic isolation rings 44 and 46 are arranged between the first phase arc-shaped magnetic poles 32F and 36P and between the second phase arc-shaped magnetic poles 34P.
, 38P, and prevents electromagnetic wave noise caused by turning on and off of the drive coil 28°; 30 from being radiated to the outside of the motor. Magnetic isolation rings 44, 46 are inner projection 44a
.

4Ga and outer projection 44b, 4G
b. inner projection 44a
, 46a is the cup 1 to part 32C of the inner yoke 32.34.
, 34C, while the outer projections 44b, 46b project into the outer yoke 36.38(7) cuts 36G, 38C. In this way,
Magnetic leakage from the cut portions 32C to 38G of the yokes 32 to 38 to the rotor 26 is completely blocked, and the magnetic flux in each phase is concentrated to the arcuate magnetic poles of the inner yoke and outer yoke, so the target magnetic field area becomes smaller. The magnetic flux density for the same magnetic pole becomes significantly higher, and the efficiency of the motor is greatly improved.

In FIG. 3, rotor 26 consists of a rotor disk 48 made of a high magnetic permeability material such as soft iron or silicon steel. A passage hole 50 for the screw 24 is provided in the center of the rotor disk 48.
Equipped with The rotor disk 48 includes arc-shaped magnetic poles 52, 54 for the first phase and the second phase, which are formed in a predetermined second phase relationship and have different radii of curvature. That is,
The arc-shaped magnetic pole 54 for the second phase is formed so as to be 180° out of phase with the arc-shaped magnetic pole for the first phase.The arc-shaped magnetic poles 52 and 54 have cutouts 52G and 54C each having a low permeance. It is formed. cutout 52
G, 54C are symmetrical positions around the motor axis,
That is, they are arranged with a phase shift of 1800. The cutouts 52C, 54G each have a clockwise extending nose or low reluctance section 52N, 54N which acts to rotate the rotor 26 clockwise - these low reluctance sections are energized when the drive coil is alternately energized. A recess or other means may be used instead of the nose as long as it always applies rotational force to the rotor in a fixed direction.The first and second phase arc-shaped magnetic poles 52,54 have a plurality of thin slits 52S extending in the radial direction, 54S respectively.

Preferably, the slits 52S, 54S are the narrow slits 32S, 365, 34S of the first and second phase stators,
They are formed to have approximately the same angular spacing as 38S and the same width. Thereby, the output torque of the motor can be dramatically increased as described later. Note that the slits 52S and 54S of the rotor 2G are arcuate magnets i52.
In order to suppress the eddy current that occurs when magnetic flux passes in the radial direction within 54, the strong magnetic flux density portion is formed into an arc-shaped magnetic pole 52.54.
By uniformly distributing the magnetic flux over the entire area, it is effective to reduce the magnetic resistance and increase the effective magnetic flux. Moreover, by suppressing the eddy current of the arc-shaped magnetic poles 52 and 54, it is possible to effectively prevent instability and resonance phenomena caused by a drop in the torque characteristics of the motor in the medium speed range or high speed range. Stable torque characteristics can be obtained from to high speed range.

In FIG. 3, the rotor 26 is equipped with a magnet 56 for position detection or rotation speed detection, and correspondingly, the stator yoke 15 is equipped with a sensor 58 such as a Hall element for position detection or rotation speed detection. The magnets 56 may be arranged in a region 60 between the inner side of the inner yaw 32 of the stator and the boss portion 12b of the frame 12, and may be arranged so as to generate an output signal every time the magnet 56 passes over the sensor 58.

In the configurations 1 and 2, when the toroidal drive coil 30 is excited, the magnetic flux generated by the coil 30 is transferred to the stator yoke 15. Inner yoke 34. The magnetic flux concentrated through the outer yoke 38 passes through the magnetic circuit F, that is, in the radial direction of the rotor 26, and attracts the circularly strong magnet w454 of the rotor 26. At this time, the rotor 26 is stationary at a stable point where the cutout 54G of the arcuate magnetic pole 54 coincides with the cut portions 34G and 38C of the inner yoke 34 and outer yoke 38 of the second phase stator. When moving on the outer yoke 38, the inner yoke 34 and the outer yoke 38 have narrow radial slits 34.
S, 38S are formed respectively, and one arcuate magnetic pole 54 is formed.
Since a radial slit 54S is also formed in the
As described below, the torque can be significantly increased depending on the number of slits. Next, when the coil 30 is turned off and the coil 28 is turned on, the low lubrication entrance 52N of the arcuate magnetic pole 52 is attracted clockwise, so the rotor 2G rotates clockwise. do. Next, when the coil 28 is turned off and the coil 30 is turned on, the nose 54N of the arcuate magnetic pole 54 is attracted clockwise, causing the rotor 26 to rotate an additional 180'' clockwise. By sequentially energizing 28 and 30, the rotor 26 rotates clockwise.

4 to 6 show a second embodiment of a two-phase, four-pole brushless motor according to the present invention, in which the same parts as in the first embodiment are given the same reference numerals, and similar parts are given the same reference numerals as in the first embodiment. Add an apostrophe (') to explain. There are three points in which the second embodiment differs from the first embodiment.

The first point is that the toroidal inner yoke 32' and toroidal outer yoke 36' of the first phase drive coil 28 are connected to a pair of cups 1 to 32'C, 3G'C and a pair of circular arc shapes separated by these cut portions. Magnetic pole 32″FT.

32'' P■, 36' PI, and 36' PIT are changed respectively.

Similarly, the toroidal inner yoke 34' and the toroidal outer yoke 38' of the second phase drive coil 30
A pair of cut portions 34'C, 38'C, and a pair of arc-shaped magnetic poles 34'P separated by these cut portions.
I, 34'PII, 38'El, and 3R'PTI, respectively. 1 arc-shaped lia pole 32' in the first phase
PI, 32' PIIt: acts as an N pole; circular fi-shaped magnet ti36' PI, 3f;' PII acts as an S pole. Similarly, arc-shaped magnetic pole 34'PI.

34' PIT acts as 514i, and 1 circular curved magnetic pole 3
4' PI, 38' pH acts as the north pole.

The second point is that the means for determining the rotational direction of the rotor disk 26' is formed on the rotor disk 26' in the first embodiment, whereas it is formed on the stator side in the second embodiment. In FIG. 5, the first phase drive coil 2
8-1 Arc-shaped magnetic pole 36'PI of the loidal outer yoke 36'.

343' PI includes a protrusion 362PP that extends counterclockwise symmetrically with respect to the X axis. Similarly, the arcuate magnetic poles 38' PI, 38' pH of the toroidal outer yoke 38' of the second phase drive coil 30 are the same as those of the first phase protrusion 3.
A protrusion 38'PP is provided which extends counterclockwise symmetrically with respect to the X-axis in the same phase as 6'PP. In such a configuration, when the rotor 26' is in a stable position, the rotor 26'
Since protrusions 36''PP and 38'PP extend in the X-axis direction and overlap with the first phase magnetic pole 52' and second phase magnetic pole 54' of 6', the rotor 26' is always attracted clockwise. 6 The third point is the first point of the rotor disk 26'.
A pair of symmetrical cutouts 52 have phase arc-shaped magnetic poles 52'.
'C into two poles, and further a second phase arc-shaped magnetic pole 5
4' is divided into two poles by a pair of symmetrical cutouts 54IC, forming a so-called four-pole structure. First phase circular arc magnetic pole 52' and second phase circular arc magnetic pole 54'
are formed to have a phase angle of 90'' with respect to each other.

Note that the slits 52'S, 5 of the rotor disk 26'
4'S is formed to form a constant skew angle with respect to the slit of the arcuate magnetic pole of the stator.

The purpose is to obtain smooth rotation of the rotor disk 26'.

The rest is the same as the first embodiment, so detailed explanation will be omitted.

1- In the configuration described above, the second phase toroidal drive coil 30
is turned on and 681 arc-shaped magnetic pole 34' PI, 3
4'Pn and arc-shaped magnetic pole 38'PI.

38' PTI is simultaneously excited and rotor disk 2
6' is attracted, and the cutout 54IC of the rotor disk 26' comes to rest at a stable point substantially coincident with the cut portion 34'C of the inner yoke 34' in FIG. Next, when the second phase toroidal drive coil 30 is turned off and the first phase toroidal drive coil 28 is turned on, the arc-shaped magnetic pole 32'P
I, 32' Pn and arc-shaped magnetic pole 36' PI, 36''p
m is excited at the same time. At this time, rotor disk 2
6′ first Aikawa arc-shaped magnetic pole 52′ is the outer yoke 36
The pair of protrusions 36' are sucked while being subjected to a clockwise rotational force by PP, so they rotate 90' clockwise, and the cutout 52'C of the rotor disk 48' connects to the cutout of the inner yoke 32'. It stops at a stable point corresponding to 32"C. Furthermore, the first phase drive coil 28 turns
When the second phase drive coil 30 is turned on after being turned off, the second phase drive coil 54' of the rotor disk 48'
is attracted by the pair of protrusions 38' PP of the outer yoke 38' while being subjected to a clockwise rotational force, and rotates clockwise by 90". In this way, the first phase and the second
Six drive coils 28 that can obtain continuous clockwise rotation by switching the excitation state of the phase drive coils 28 and 30.
．． 30 may be energized in a known two-phase manner, or if the drive coils 28 and 30 are connected to an AC power source and a capacitor is connected to one of the coils, it will function as an AC motor.

In the examples described above, the rotor was explained as being made of a disk with high magnetic permeability, but the rotor may have a structure in which arc-shaped magnetic poles made of a high permeability material or a permanent magnet are embedded in a disk made of a non-magnetic material. . Furthermore, by changing the thickness of the rotor disk in the axial direction, the convex portion facing the stator may form an arc-shaped magnetic pole, and the four parts may be used as low-permeance sections instead of cut-outs. It may also be constituted by a magnet.

〔effect〕

As is clear from the following 1], in the two-phase brushless motor of the present invention, the magnetic flux generated by the toroidal drive coil in each phase is concentrated on the toroidal inner yoke and the toroidal outer yoke, and each phase is distributed in multiple directions in the radial direction in the stator. , the volume ratio of the windings per unit volume of the motor can be significantly increased. Therefore, the output torque of the motor is driven by the number of turns n of the windings and the square of the current )2, it is possible to achieve high efficiency that could not be achieved in the past. As a result, the brushless motor can be made extremely heavy and lightweight, with high-speed response and high performance. especially,
Even if the distance between the arc-shaped magnetic poles of each phase becomes smaller when a two-phase brushless motor is made to be super heavy and lightweight, the magnetic flux generated by the coil can be reduced because a magnetic isolation ring is placed between the magnetic poles of each phase. Maximum electromagnetic energy is obtained because all magnetic flux is more concentrated between the opposing pole faces of the stator and rotor, without leaking into the air gap between the poles. Therefore, *magnetic energy conversion efficiency is extremely high, and large energy saving efficiency can be obtained. Furthermore, the four sides of the cross section of the drive coil for each phase are surrounded by good thermal conductors, and these good thermal conductors are thermally conductive to the stator yoke and housing, which are also good thermal conductors, so that the coil The heat dissipation area of the coil is greatly increased and the heat dissipation of the coil is very efficient, and the motor overload is significantly increased. Furthermore, since the drive coils of each phase are surrounded by the inner yoke, outer yoke, stator yoke, and magnetic isolation ring, radiation of electromagnetic noise from the motor to the outside can be significantly reduced. Furthermore, since a large number of slits are formed in the rotor disk and the stator magnetic poles in parallel with the magnetic path, magnetic reaction due to fluctuating magnetic flux is effectively prevented and the effective cross-sectional area of the magnetic circuit is increased.

By reducing the reluctance, the total magnetic flux can be significantly increased. Because slits are formed in the arc-shaped magnetic poles of the drive coil of each phase and the arc-shaped magnetic poles of the rotor,
As the rotor rotates, the range of changes in the magnetic field strength and magnetic flux density between opposing magnetic poles of the stator and rotor increases significantly compared to the case of a flat magnetic pole surface, and the output torque of the motor becomes extremely large. Therefore, a two-phase brushless motor that is capable of high-speed response, is smaller, lighter, and has higher performance than ever before is realized. In addition, the rotor disc has a large-area cutout, which significantly reduces the overall weight of the rotor disc, resulting in extremely low rotor inertia.
Due to the large rotational torque, high-speed response and precise positioning are possible, as well as excellent slewing characteristics. In addition,
The rotor disk is solid and there are no brushes or commutators, so it can be used at high speeds. Moreover, the stator and rotor disk can use cheap raw materials,
Furthermore, the structures of the stator, rotor disk, and drive coil have been extremely simplified, making machining and assembly easier.
It can be manufactured at low cost in L, and the cost can be reduced by a considerable amount. The motor of the present invention has a simple structure and is sturdy, so it is suitable for high-speed indoor use, can withstand frequent acceleration and deceleration operations, has excellent resistance to high and low temperature environments, and has no deterioration in operating performance due to continuous use. It has a long lifespan.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a two-phase brushless motor according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken from the line ■-■ in FIG.
FIG. 3 is a plan view of the rotor shown in FIG. 1. FIG. 4 is a sectional view of a second embodiment of the two-phase brushless motor of the present invention, FIG. 5 is a sectional view taken from the line ■-■ in FIG. 4, and FIG. Each is shown below. 12・・・・・・・・・Frame 14・・・・・・
...Stator 26 ...Rotor 28.30 ...... Toroidal drive coil 3
2.34......Toroidal Inner York 3
6.38......Toroidal outer yoke 32P, 341m, 36P, 38F...Conical magnetic pole 44.46...Magnetic isolation ring patent application People Hi-Tech Institute Co., Ltd. z3 diagram

Claims (8)

[Claims] (1) Toroidal drive coils for the first and second phases having different radii of curvature arranged concentrically, and a first toroidal drive coil for magnetic flux concentration extending in the axial direction on the inside and outside of the first phase drive coil. a toroidal inner yoke and a first toroidal outer yoke, and a second toroidal inyoke and a second toroidal outer yoke for magnetic flux concentration extending in the axial direction on the inside and outside of the second phase drive coil. and a rotor disk having first and second magnetic poles formed in a predetermined first phase relationship at different radii of curvature,
at least one of the toroidal inyoke and the first toroidal outer yoke includes a first phase magnetic pole,
a second phase magnetic pole in which at least one of the second toroidal inyoke and the second toroidal outer yoke is formed in a predetermined second phase relationship with respect to the first phase magnetic pole; The first and second magnetic poles of the rotor disk are each provided with a low reluctance portion that is attracted in a fixed direction by the first and second phase magnetic poles of the stator, and the first and second magnetic poles of the rotor disk and a second magnetic pole and the first and second phases of the stator.
A brushless motor characterized by having Aikawa magnetic poles facing each other through an air gap. (2) the first phase and second phase magnetic poles of the stator include a plurality of eddy current prevention slits extending in the radial direction;
2. The brushless motor according to claim 1, wherein the first and second magnetic poles of the rotor disk are provided with a plurality of eddy current prevention slits extending in a radial direction. (3) The brushless motor according to claim 2, wherein the slits of the rotor disk form a constant skew angle with respect to the slits of the first and second phase magnetic poles. (4) The stator is connected to the first phase drive coil and the second phase drive coil.
3. The brushless motor according to claim 1, further comprising a magnetic isolation ring disposed in front of the phase drive coil. (5) Toroidal drive coils for the first and second phases having different radii of curvature arranged concentrically, and a first toroidal drive coil for magnetic flux concentration extending in the axial direction on the inside and outside of the first phase drive coil. a toroidal inner yoke and a first toroidal outer yoke, and a second toroidal inyoke and a second toroidal outer yoke for magnetic flux concentration extending in the axial direction on the inside and outside of the second phase drive coil. and a rotor disk having first and second magnetic poles formed in a predetermined first phase relationship at different radii of curvature,
at least one of the toroidal inyoke and the first toroidal outer yoke includes a first phase magnetic pole,
a second phase magnetic pole in which at least one of the second toroidal inyoke and the second toroidal outer yoke is formed in a predetermined second phase relationship with respect to the first phase magnetic pole; The first and second phase magnetic poles of the stator each include a low reluctance portion for applying rotational force in a fixed direction to the rotor disk, and the first and second phase magnetic poles of the rotor disk A brushless motor characterized in that the first phase and second phase magnetic poles of the stator are opposed to each other with an air gap interposed therebetween. (6) The first phase and second phase magnetic poles of the stator include a plurality of eddy current prevention slits extending in the radial direction,
6. The brushless motor according to claim 5, wherein the first and second magnetic poles of the rotor disk are provided with a plurality of eddy current prevention slits extending in a radial direction. (7) The brushless motor according to claim 6, wherein the slits of the rotor disk form a constant skew angle with respect to the slits of the first and second phase magnetic poles. (8) The stator is connected to the first phase drive coil and the second phase drive coil.
7. The brushless motor according to claim 5, further comprising a magnetic isolation ring disposed in front of the phase drive coil.