JP2002281722A - Outer rotor motor and electric bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outer rotor motor and an electric bicycle capable of attaining size and weight reductions, high output torque and small torque ripple. SOLUTION: This outer rotor motor 1 has a stator 2 generating a rotating field, and an outer rotor 3 disposed at the outer periphery of the stator 2 with a clearance 4 so as to rotate freely and where a plurality of permanent magnets 11 are disposed in a circumferential direction. The outer rotor 3 where the permanent magnets 11 are disposed in the circumferential direction at a prescribed interval is disposed at a rotor core 9 having an annular yoke 12 at an outer periphery part, protruding poles 13 facing an outer periphery of the stator 2 with the clearance 4 are integrated and protruding-constituted between the permanent magnets from the yoke part 12, and the permanent magnets 11 are displaced so as to be deformed continuously or intermittently in the circumferential direction as it moves in the axial core direction of the outer rotor 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer rotor motor and an electric vehicle using the same.

[0002]

2. Description of the Related Art Electric motors include an inner rotor type motor and an outer rotor type motor. An outer rotor type motor is provided with an outer rotor having a permanent magnet for a field outside a stator on which a winding is applied, and applies a three-phase alternating current to the winding of the stator based on phase information from a position sensor. It is configured to generate a rotating magnetic field by flowing, and to rotate the outer rotor.

[0003] The outer rotor motor has a feature that, since the rotor is on the outside, the outer diameter of the rotor can be made larger than that of the inner rotor motor for the same motor size, so that the generated torque can be made higher than that of the inner rotor motor. is there. Therefore, it is suitable for electric equipment that requires a larger torque.

Accordingly, for example, Japanese Patent Application Laid-Open No. 9-506236.
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-175, the present invention is suitably applied to an in-wheel motor in an electric vehicle in which wheels are directly driven by a motor.

In the outer rotor motor 31, as shown in FIG. 8, a winding 34 is applied to each tooth 33 formed on the outer periphery of a stator 32, and a cylindrical rotor body 36 is provided outside the stator 32. An outer rotor 35 having a plurality of permanent magnets 37 circumferentially disposed on an inner surface thereof is rotatably disposed.

[0006]

As described above, the outer rotor motor used for the in-wheel motor for an automobile needs to be small and lightweight in order to reduce the unsprung weight of the vehicle body, and it is necessary to further increase the height. A torque motor is required.

However, in the outer rotor motor 31 having the structure shown in FIG. 8, the outer rotor 35 has a cylindrical rotor body 3 made of an iron plate having a small thickness in the radial direction.
6, the permanent magnets 37 are fixed to the inner surface at predetermined intervals, so that the rotating magnetic field generated by the stator 32 and the permanent magnets 3 are fixed.
Since only the magnet torque due to the interaction of No. 7 can be used, there is a problem that it is difficult to obtain a sufficient output torque. That is, of the magnetic flux paths through which the magnetic flux by the stator 32 passes through the inside of the outer rotor 35, a magnetic flux path 38 in the d-axis direction penetrating the permanent magnet 37 and a magnetic flux path 39 in the q-axis direction advanced by 90 degrees in electrical angle from the d-axis. , A permanent magnet 37 and a permanent magnet 37 having the same magnetic permeability as air, respectively.
Since there is almost no difference in inductance due to the passage of the air layer between the 7, the reluctance torque cannot be used. Further, since the space between the permanent magnets 37 is an air layer having a small magnetic permeability, there is a problem that the magnetic flux distribution changes abruptly and the torque ripple is large.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide an outer rotor motor and an electric vehicle which are small and lightweight, have high output torque, and have small torque ripple.

[0009]

SUMMARY OF THE INVENTION An outer rotor motor according to the present invention comprises a stator for generating a rotating magnetic field, and a plurality of permanent magnets disposed in a circumferential direction on the outer periphery of the stator so as to be rotatable with a gap therebetween. The outer rotor is provided with permanent magnets at predetermined intervals in the circumferential direction on a rotor core having a ring-shaped yoke portion on the outer periphery, and a gap is provided between the yoke portion and the permanent magnets on the outer periphery of the stator. The permanent magnets are arranged so as to protrude integrally, and the permanent magnets are continuously or intermittently displaced in the circumferential direction as they move in the axial direction of the outer rotor. Since the outer rotor is used, the output torque per motor size is large, and the magnet torque generated between the rotating magnetic field generated by the stator and the permanent magnet is reduced. Both the reluctance torque generated by the passage of the magnetic flux of the rotating magnetic field through the magnetic path having a large inductance formed by the yoke portion and the salient pole portion of the rotor core are used, so that a high output torque can be obtained with small size and light weight. Further, since the permanent magnets are skewed in the rotational direction, torque ripple can be reduced, so that an outer rotor motor that is small, lightweight, has high output torque, and has small torque ripple can be obtained.

The amount of displacement of the permanent magnet in the circumferential direction is defined as an electrical angle, and the electrical angle of the circumferential length of the permanent magnet is defined as θ.
When (80−θ) / 3 to (180−θ), the torque ripple can be greatly reduced without significantly lowering the output torque. That is, if the displacement amount is less than one third of (180-θ), the skew amount is too small and the effect of reducing the torque ripple is not sufficient. If the displacement amount exceeds (180-θ), the effect of reducing the torque ripple is reduced. Even if it becomes larger, there will be a portion overlapping in the axial direction at the same circumferential position as the adjacent permanent magnet of the opposite polarity, and the output torque will be sharply reduced.

The radial thickness of the outer rotor is t ₀ ,
Assuming that the radial thickness of the permanent magnet is t, 1/3 ≦ t / t ₀ ≦
When the circumferential length per single pole of the outer rotor is θ ₀ and the circumferential length of the permanent magnet is θ, 0.4 ≦ θ /
When θ ₀ ≦ 0.9, the yoke width is secured, the inductance of the magnetic path formed by the yoke portion and the salient pole portion is increased, and the difference between the inductance and the magnetic path passing through the permanent magnet is secured, A large reluctance torque can be obtained, and the output torque can be increased. According to the analysis result, a torque 2.3 times higher than that of the conventional example using only the magnet torque was obtained.

Further, 2/5 ≦ t / t ₀ ≦ 1/2,
When 0.45 ≦ θ / θ ₀ ≦ 0.55, the torque can be further increased, and the torque ripple can be improved by increasing the width of the salient pole portion. According to the analysis result, the conventional example using only the magnet torque is not used.
Five times the torque was obtained, and the torque ripple was reduced by 40%.

If one or both of the rotor core and the stator core are formed by laminating electromagnetic steel sheets, the rotor core and the stator core are finely divided in the axial direction, so that eddy current generated in the core can be suppressed. Efficiency can be improved.

Further, when one or both of the rotor core and the stator core are formed by a powder metallurgy molded product, an optimally complex core can be manufactured at low cost.

Further, when one or both of the rotor core and the stator core are formed by combining core pieces divided into one pole or plural poles in an annular shape, when the electromagnetic steel sheets are laminated, the core piece is formed. Can be eliminated, the winding can be performed easily and with good productivity, and the cost can be reduced.

In the electric vehicle of the present invention, the stator of the outer rotor motor is fixed to an axle side of a wheel, and the outer rotor is fixed to a wheel of a wheel rotatably supported with respect to the axle. High output,
A highly efficient electric vehicle can be provided.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an outer rotor motor according to the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes an outer rotor motor, the overall shape of which is naturally circular.
Only one minute is shown. The outer rotor motor 1 is composed of a stator 2 and an outer rotor 3 rotatably disposed on the outer periphery of the stator 2 with a small gap 4 therebetween.

The stator 2 has a ring-shaped yoke 6 on the inner periphery of a stator core 5 formed by laminating electromagnetic steel sheets.
3n (n is a natural number) teeth 7 are provided on the outer peripheral portion, and the windings 8 are applied to each tooth 7 by concentrated winding. The rotational position of the outer rotor 3 is detected by a sensor (not shown) or the like, and a three-phase alternating current is applied to each winding 8 to form a rotating magnetic field.

As shown in FIG. 2, the outer rotor 3 has 2n (the above-mentioned n) concave portions 10 formed at predetermined intervals in an inner peripheral portion of a rotor core 9 formed by laminating electromagnetic steel sheets. Permanent magnets 1 such as rare earth magnets and ferrite magnets
1 is arranged and fixed. The rotor core 9 has a ring-shaped yoke portion 12 having a predetermined width in the radial direction on an outer peripheral portion, and the permanent magnet 1 is integrally formed from the yoke portion 12.
A configuration is provided in which salient pole portions 13 projecting between 1 and 11 are provided. The inner peripheral end of the salient pole portion 13 is opposed to the outer periphery of the stator 2 with a small gap 4 described above. In addition, a gap of 4 or more may be provided between the inner peripheral end of the salient pole portion 13 and the stator 2 as necessary, or an appropriate material may be interposed.

As shown in FIG. 3, the permanent magnet 11 is divided into a plurality of pieces in the axial direction of the outer rotor 3, and the divided magnet blocks 11a and 11b are circumferentially arranged at one end and the other end in the axial direction. Is displaced by the displacement amount δ.
Hereinafter, this displacement amount δ is referred to as a skew amount. The skew amount δ of the magnet blocks 11a and 11b is an electrical angle, and δ = (1) where θ is the electrical angle of the circumferential length of the permanent magnet 11.
It is preferable to set so as to obtain the optimum characteristics within the range of (80−θ) / 3 to (180−θ).

Instead of dividing the permanent magnet 11 into a plurality of pieces in the axial direction, as shown in FIG. 4, the permanent magnet 11 and the salient pole portion 13 are displaced in the axial direction by one end and the other end in the circumferential direction. The shape may be inclined in the circumferential direction.

In the above configuration, the magnetic flux generated by the current flowing through the winding 8 passes through the inside of the outer rotor 3, and the magnetic flux
And a magnetic flux path 15 in the q-axis direction that is advanced by an electrical angle of 90 degrees from the d-axis. The magnetic flux path 15 in the q-axis direction in this embodiment passes through the salient pole portion 13, the yoke portion 12, and the salient pole portion 13. . Therefore, compared to the inductance Ld of the magnetic flux path 14 in the d-axis direction passing twice through the permanent magnet 11 having the same magnetic permeability as air, the salient pole portion 13, the yoke portion 12, and the salient pole portion provided on the rotor core 9 having high magnetic permeability. The inductance Lq of the magnetic flux path 15 in the q-axis direction passing through the pole portion 13 is high, and a large reluctance torque is obtained by the difference (Lq-Ld) of the inductance.

That is, the generated torque T of the motor is: T = Tm + Tr (1) Tm = PφIcosβ (2) Tr = 0.5 P (Lq−Ld) I ² sinβ (3) where Tm: magnet torque, Tr: Reluctance torque, P: number of pole pairs, φ: linkage magnetic flux by the field permanent magnet, I: current, β: phase of current I based on q-axis current, increasing (Lq−Ld) As a result, a large reluctance torque can be obtained.

Further, by skewing the permanent magnet 11 in the rotation direction and limiting the skew amount δ as described above, the torque ripple can be greatly reduced without greatly reducing the output torque. That is, δ is (180−
is less than one-third of θ), the skew amount is too small, and the effect of reducing the torque ripple is not sufficient.
-Θ), even if the torque ripple reduction effect is greater, there is a portion that overlaps with the adjacent permanent magnet of the opposite polarity in the axial direction at the same circumferential position, resulting in a sharp decrease in output torque. It is because it becomes.

Next, the shape and dimensions of each part for obtaining a larger torque in the above configuration will be described below.

The width of the yoke 6 and the teeth 7 of the stator core 5 of the stator 2 is defined as w1 with the width of the teeth 7 of the stator core 5 as w1 and the width of the yoke 6 as w2.
And w2 can be made substantially the same to suppress local saturation of the magnetic flux, and it is preferable to set the range of 0.8 ≦ w1 / w2 ≦ 1.2.

Assuming that the total thickness of the outer rotor 3 in the radial direction of the rotor core 9 is t ₀ , and the thickness of the permanent magnet 11 in the radial direction is t, 1/3 ≦ t / t ₀ ≦ 2/3. Assuming that the circumferential length per single pole is θ ₀ and the circumferential length of the permanent magnet 11 is θ, 0.4 ≦ θ / θ ₀ ≦ 0.9, the yoke part 12 becomes 2/1/2 of t ₀ . A width of 3 to 1/3 is ensured, and the salient pole portion 13 is at least 1 of θ ₀ .
/ 10 is secured, the inductance Lq of the magnetic flux path 15 in the q-axis direction formed by the yoke portion 12 and the salient pole portion 13 is increased, and the inductance Ld of the magnetic flux path 14 in the d-axis direction passing through the permanent magnet 11 is increased. , A large reluctance torque is obtained, and the output torque can be increased. According to the analysis results, for the same motor outer diameter R,
2.3 times as much torque as that of the conventional example using only the magnet torque was obtained.

Further, 2/5 ≦ t / t ₀ ≦ 1/2,
When 0.45 ≦ θ / θ ₀ ≦ 0.55, the torque can be further increased, and the torque ripple can be improved by increasing the width of the salient pole portion 13. According to the analysis results, a torque 2.5 times as large as that of the conventional example using only the magnet torque was obtained, and the torque ripple was 4 times.
0% reduction was achieved.

In the above description of the embodiment, the stator core 5 and the rotor core 9 have been described as being integrally cylindrical. However, in the actual manufacturing process of the outer rotor motor 1, FIG.
As shown in the figure, it is preferable that the stator core 5 is configured by combining stator core pieces 16 divided for each tooth 7, and the rotor core 9 is configured by combining rotor core pieces 17 divided at the boundary between poles.

More specifically, the stator core pieces 16 are formed by laminating electromagnetic steel sheets and fixing them by welding or the like. Protrusions 16a and grooves 16b extending in parallel with the motor shaft are provided on split surfaces on both sides of each stator core piece 16 so as to fit each other when the stator core pieces 16 are combined. Next, the winding 8 is applied to the teeth 7 of each stator core piece 16. After that, the stator core pieces 16 are combined in an annular shape and fixed integrally by welding or the like. At that time,
By fitting the projection 16a and the groove 16b, the stator core piece 1
6 can be easily and reliably positioned, and the strength of the stator core 5 after the combination can be ensured. Thus, the stator 2 is configured at the same time as the stator core 5 is configured.

The rotor core piece 17 is formed by laminating electromagnetic steel sheets and fixing them by welding or the like. Each rotor core piece 17 is formed with a concave portion 10 in which the permanent magnet 11 is disposed, and the divided surfaces on both sides of each rotor core piece 17 extend in parallel with the motor shaft so as to fit each other when the rotor core pieces 17 are combined. A projection 17a and a groove 17b are provided. Next, the permanent magnet 1 is inserted into the recess 10 of each rotor core piece 17.
1 is arranged and fixed integrally by caulking or bonding. Thereafter, the respective rotor core pieces 17 are combined in an annular shape and fixed integrally by welding or the like. At this time, the projection 17a and the groove 17b
By this, the positioning of the rotor core piece 17 can be performed easily and reliably, and the strength of the rotor core 9 after the combination can be ensured. Thus, the outer rotor 3 is formed at the same time as the rotor core 9 is formed.

The outer rotor motor 1 is formed by combining the stator 2 and the outer rotor 3 formed as described above.
Is completed. Thus, the divided stator core pieces 1
By manufacturing the stator 2 and the outer rotor 3 by combining the rotor core piece 6 and the rotor core piece 17, it is possible to eliminate waste of material when punching out the electromagnetic steel sheet by a press or the like, and it is possible to greatly reduce the manufacturing cost. Further, even in the winding step, the winding 8 can be applied to the single tooth 7 of the stator core piece 16 easily and with high productivity. Also,
In the step of disposing the permanent magnet 11 with respect to the outer rotor 3,
The rotor core pieces 17 can be arranged and fixed easily and with good productivity. As a result, the outer rotor motor 1
Can be manufactured at low cost.

FIG. 5 shows an example in which the stator core piece 16 is divided for each single tooth 7 and the rotor core piece 17 is divided at the boundary between the poles. However, the present invention is not limited to this. For example, as shown in FIG. 6, the stator core piece 16 may be divided for every three teeth 7 and the rotor core piece 17 may be divided for every two poles at the boundary.

The outer rotor motor 1 configured as described above is applied to, for example, an in-wheel motor that directly drives wheels of an electric vehicle, as shown in FIG.

In FIG. 7, reference numeral 20 denotes a wheel of an electric vehicle, reference numeral 21 denotes an axle thereof, reference numeral 22 denotes a wheel rotatably mounted on the axle 21, and reference numeral 24 denotes a wheel mounted on a rim 23 on the outer periphery of the wheel 22. The outer rotor motor 1 is a tire, and is disposed in the wheel 22. The stator 2 of the outer rotor motor 1 is fixed to the outer periphery of a support bracket 25 fixed to the axle 21, and the outer rotor 3 is fixed to the inner surface of the rim 23 of the wheel 22.

As described above, the outer rotor motor 1
According to the in-wheel motor drive type electric vehicle incorporating the vehicle, since the drive device is stored inside the wheels 20, the space on the vehicle body side can be widened and the space can be effectively used, and the vehicle body can be downsized. In addition, the weight of the vehicle body can be reduced, and the direct drive system in which the outer rotor 3 is directly fixed to the wheel 22 can further promote reduction in size and weight. Further, since the outer rotor motor 1 can obtain a high output torque using both the magnet torque and the reluctance torque as described above and has a small torque ripple, it is possible to provide a high-output, high-efficiency, high-performance electric vehicle. it can.

In the description of the above embodiment, the stator core 5 and the rotor core 9 are formed by laminating electromagnetic steel sheets, but they may be formed by powder metallurgy. When electromagnetic steel sheets are laminated, the cross-sectional shape of the core is limited to the same across both ends. However, by forming a powder metallurgy product, grooves for accommodating the windings 8 at both ends in the axial direction of the stator core 5 are formed. Stator core 5
In addition, even if the rotor core 9 has a complicated shape, the rotor core 9 can be manufactured at an optimum shape at low cost.

In the above embodiment, the outer rotor 3
As an example of the arrangement of the permanent magnets 11 in the above, the permanent magnet 11 having a substantially flat plate shape or an arc-shaped cross section having the same diameter as the inner peripheral diameter is disposed in the concave portion 10 formed on the inner periphery. In the state where the yoke portion 12 is left in the outer peripheral portion, the permanent magnet 11 having a small radius of curvature and a circular arc shape or a mountain cross section is used.
May be buried to increase the flux linkage by the permanent magnet 11, and a slit may be formed along the circumferential direction at a portion of the yoke portion 12 facing the outer peripheral side of the permanent magnet 11, and the slit may be formed in the d-axis direction. Magnetic flux path 14 and magnetic flux path 15 in the q-axis direction
(Lq−Ld) may be further increased.

The outer rotor motor 1 of the above embodiment can be applied to various electric devices other than the in-wheel motor of an electric vehicle, and can provide a small, high-output, and high-efficiency electric device.

[0041]

According to the outer rotor motor of the present invention,
As is clear from the above description, the outer rotor is provided on the rotor core having a ring-shaped yoke portion on the outer peripheral portion, permanent magnets are disposed at predetermined intervals in the circumferential direction, and a gap is formed between the yoke portion and the permanent magnet on the outer periphery of the stator. Since the salient pole portions opposing each other are integrally protruded, and the permanent magnets are arranged so as to be continuously or intermittently displaced in the circumferential direction as they move in the axial direction of the outer rotor, the outer rotor type is used. The output torque per motor size can be increased by
In addition, the magnet torque generated between the rotating magnetic field generated by the stator and the permanent magnet and the reluctance torque generated when the magnetic flux of the rotating magnetic field passes through a magnetic path having a large inductance formed by the yoke portion and the salient pole portion of the rotor core. Both can be used, small and lightweight, high output torque can be obtained, and the torque ripple can be reduced by skewing the permanent magnet in the rotational direction.Thus, small and lightweight, high output torque can be obtained and torque ripple can be reduced. A small outer rotor motor can be obtained.

The amount of displacement of the permanent magnet in the circumferential direction is defined as an electrical angle, and the electrical angle of the circumferential length of the permanent magnet is defined as θ.
When (80−θ) / 3 to (180−θ), the torque ripple can be greatly reduced without significantly lowering the output torque.

The radial thickness of the outer rotor is t ₀ ,
Assuming that the radial thickness of the permanent magnet is t, 1/3 ≦ t / t ₀ ≦
When the circumferential length per single pole of the outer rotor is θ ₀ and the circumferential length of the permanent magnet is θ, 0.4 ≦ θ /
When θ ₀ ≦ 0.9, the yoke width is secured, the inductance of the magnetic path formed by the yoke portion and the salient pole portion is increased, and the difference between the inductance and the magnetic path passing through the permanent magnet is secured, A large reluctance torque can be obtained and the output torque can be increased. Further, when 2/5 ≦ t / t ₀ ≦ 1/2 and 0.45 ≦ θ / θ ₀ ≦ 0.55, a higher torque can be achieved. At the same time, torque ripple can be improved.

When the rotor core and the stator core are formed by laminating electromagnetic steel sheets, the core is finely divided in the axial direction, so that eddy current generated in the core can be suppressed and the efficiency can be improved.

Further, when the rotor core and the stator core are formed of a powder metallurgy molded product, an optimally complex core can be manufactured at low cost.

Further, when the rotor core and the stator core are configured by combining divided cores divided into one pole or plural poles in an annular shape, when the electromagnetic steel sheets are laminated,
It is possible to eliminate waste of material when punching and forming the divided cores, to perform winding easily and with good productivity, and to reduce costs.

In the electric vehicle of the present invention, the stator of the outer rotor motor is fixed to the axle side of the wheel, and the outer rotor is fixed to the wheel of the wheel rotatably supported with respect to the axle. High output,
A highly efficient electric vehicle can be provided.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of an outer rotor motor according to an embodiment of the present invention.

FIG. 2 is a perspective view of the rotor core of the embodiment.

FIG. 3 is an explanatory diagram of a skew arrangement state of permanent magnets in the embodiment.

FIG. 4 is an explanatory diagram of another skew arrangement state of the permanent magnet in the embodiment.

FIG. 5 is an explanatory diagram of an assembling process of the outer rotor motor of the embodiment.

FIG. 6 is an explanatory diagram of another assembly process of the outer rotor motor of the embodiment.

FIG. 7 is a sectional view of a wheel of an electric vehicle in which the outer rotor motor of the embodiment is incorporated.

FIG. 8 is a cross-sectional view of a part of a conventional outer rotor motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer rotor motor 2 Stator 3 Outer rotor 4 Crevice 9 Rotor core 11 Permanent magnet 12 Yoke part 13 Salient pole part 17 Rotor core piece 20 Wheel 21 Axle 22 Wheel

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H02K 1/24 H02K 1/24 A 5H622 1/27 502 1/27 502A 1/28 1/28 D 7 / 14 7/14 Z 19/10 19/10 A 29/00 29/00 Z (72) Inventor Masaki Tame 1006 Ojimon Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 5H002 AA09 AB06 AB07 AC02 AC04 AE06 AE08 5H019 AA02 AA09 AA10 CC04 CC09 DD01 EE14 EE16 FF01 GG05 5H607 AA12 BB01 BB07 BB09 BB14 BB17 CC05 FF01 FF12 5H619 AA01 BB01 BB06 BB13 BB15 BB24 PP01 PP02 PP01 PP02 PP06 PP12 PP19

Claims (8)

[Claims] 1. An outer rotor motor comprising: a stator for generating a rotating magnetic field; and an outer rotor having a plurality of permanent magnets disposed circumferentially in a rotatable manner with a gap provided on the outer periphery of the stator. The permanent magnets are arranged at predetermined intervals in the circumferential direction on a rotor core having a ring-shaped yoke portion on the outer peripheral portion, and the salient pole portions opposed to each other with a gap between the yoke portion and the permanent magnet on the outer periphery of the stator are integrally formed. An outer rotor motor, wherein the permanent magnet is disposed so as to be continuously or intermittently displaced in the circumferential direction as it moves in the axial direction of the outer rotor. 2. The amount of displacement of the permanent magnet in the circumferential direction is represented by an electrical angle, and the electrical angle of the circumferential length of the permanent magnet is represented by θ.
The outer rotor motor according to claim 1, wherein (0−θ) / 3 to (180−θ). 3. Assuming that the radial thickness of the outer rotor is t ₀ and the radial thickness of the permanent magnet is t, 1/3 ≦ t / t ₀ ≦ 2 /
3, the peripheral length per single pole of the outer rotor is θ ₀ , and the peripheral length of the permanent magnet is θ, 0.4 ≦ θ /
2. The outer rotor motor according to claim 1, wherein θ ₀ ≦ 0.9. 4. The condition of 2/5 ≦ t / t ₀ ≦ 1/2, 0.4
4. The outer rotor motor according to claim 3, wherein 5 ≦ θ / θ ₀ ≦ 0.55. 5. The outer rotor motor according to claim 1, wherein one or both of the rotor core and the stator core are formed by laminating electromagnetic steel sheets. 6. The outer rotor motor according to claim 1, wherein one or both of the rotor core and the stator core are formed of a powder metallurgy molded product. 7. The outer rotor according to claim 1, wherein one or both of the rotor core and the stay core are formed by combining core pieces divided into one pole or plural poles in an annular shape. motor. 8. A stator in the outer rotor motor according to claim 1, wherein the stator is fixed to an axle side of a wheel.
An electric vehicle having an outer rotor fixed to wheels of wheels supported rotatably with respect to an axle.