JP2000014111A - Outer-side rotation type permanent-magnet motor and elevator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a less-vibration and low-noise epicycloidal permanent- magnet motor provided with a means which avoids the resonance of the higher harmonic constituent of electromagnetic force with the circular vibration of the mechanical structure of a motor, and prevents the dislocation in the circumferential direction of permanent magnets. SOLUTION: An outer-side rotation permanent-magnet motor comprises a stator 31 including stator windings and a cylindrical rotor provided with permanent magnets 220 whose rotating shaft is supported coaxially by that of the stator 31 and which is divided in the circumferential direction inside an outside circumferential wall 21. In this motor, a highly rigid fixing means (rib) 222 is provided which avoids the resonance of the higher harmonic constituent of electromagnetic force caused by the stator windings with the circular vibration of the mechanical structure of the motor, and prevents the dislocation in the circumferential direction of the permanent magnets. This structure can reduce the vibration and noise of the outer-side rotation permanent-magnet significantly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external rotation type permanent magnet motor and an elevator employing the motor as a hoisting power, and more particularly to vibration and noise generated in the external rotation type permanent magnet motor by an electromagnetic excitation force. The present invention relates to a stiffening structure for reduction.

[0002]

2. Description of the Related Art In an external rotation type permanent magnet motor, a permanent magnet is mounted on a rotor side, and a coil is wound around a tooth portion of an inner stator to generate a rotating magnetic field between the permanent magnet and the stator coil. Generate and rotate the outer rotor. The magnetic flux density generated by the rotating magnetic field has a harmonic component, and an electromagnetic exciting force acts on the rotor, so that vibration and noise are generated.

In order to solve such a problem, see, for example,
In the motor described in Japanese Patent No. 164254, an outer peripheral edge of a reinforcing ring made of a non-magnetic material is fixed to an open end of an outer peripheral wall of a rotor having a permanent magnet attached to the inside thereof, thereby reducing the annular rigidity of the outer peripheral wall of the rotor. It increases noise and vibration, and prevents permanent magnet displacement.

[0004]

The external permanent magnet motor to which the present invention is applied has a permanent magnet divided and mounted inside the outer peripheral wall of the rotor. In this case, the rigidity of the entire outer peripheral wall can be increased by simply fixing the reinforcing ring to the opening end of the outer peripheral wall as in the above-described prior art, even if it is useful to increase the annular rigidity of a part of the rotor outer peripheral wall. It cannot be enhanced. Therefore, the effect of reducing noise generated from the entire outer peripheral wall is small, and the effect of maintaining the circumferential alignment of the divided permanent magnets cannot be expected. If the permanent magnets cannot be aligned and held in the circumferential direction, the electromagnetic force distribution also fluctuates.

In general, the harmonic component of the electromagnetic force contains a large number of spatial order components and time order components that excite ring vibration of a mechanical structure. In particular, in the case of an inverter-driven motor, the frequency of the annular vibration mode of the mechanical structure of the motor and the frequency of the electromagnetic force generated by the inverter are in a resonance state because the rotation speed range is wide, which causes vibration and noise. Become.

In order to reduce the vibration and noise of the inverter-driven epicyclic permanent magnet motor, it is necessary to avoid the resonance between the harmonic component of the electromagnetic force by the inverter and the annular vibration of the mechanical structure of the motor. It is also important to prevent the circumferential displacement of the permanent magnet caused by the centrifugal force due to the rotation.

[0007] The places where elevator equipment as an application field including motors are installed can be roughly classified as follows.
There will be a hoistway and a machine room. In the hoistway, a car, guide rails for guiding the car up and down, and the like are installed. The machine room is provided with a hoist that drives the car, a motor that is a power source for the hoist, a control panel that controls the elevation of the car, and the like.

Conventionally, the installation of a machine room has been obligatory in accordance with the Building Standards Law. However, for a home elevator, a design guideline was stated that "a drive device including a control device and the like can be installed in a hoistway". . This design guideline is described in the "Elevator Design Guideline-Part 1-3 Guideline for Design of Home Elevators" published by the Japan Elevator Association (issued on December 15, 1993). I have.

At the present time, the idea that "a drive device including a control device and the like can be installed in a hoistway" is based on the idea of a home elevator, that is, an elevator for a private house, compiled by a study committee installed at the Japan Building Center. It is a guideline for the design, structure, etc. of the building and does not conform to the provisions of elevators based on the Building Standards Law, but it is expected that deregulation will be expanded in the future and applied to general home elevators.

At this time, since a hoist and a motor serving as a power source for the hoist are installed in a narrow hoistway, it is of course required to reduce the size of the motor. It is even more demanded that vibration and noise are not transmitted to the car.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent resonance between a harmonic component of an electromagnetic force and an annular vibration of a mechanical structure of a motor, and to provide a low-vibration device having means for preventing a circumferential displacement of a permanent magnet. Another object of the present invention is to provide an epimotor permanent magnet motor having low noise and an elevator employing the motor as a power source.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a stator including a stator winding and a rotating shaft which is coaxially supported by the stator and which is circumferentially mounted inside an outer peripheral wall. Avoids the resonance between the harmonic component of the electromagnetic force due to the stator winding and the ring vibration of the mechanical structure of the motor, in an external rotation type permanent magnet motor consisting of a cylindrical rotor equipped with divided permanent magnets. The present invention proposes an external rotation type permanent magnet motor including a highly rigid fixing means for fixing the circumferential position of the divided permanent magnet to a position for preventing the circumferential displacement of the permanent magnet.

The high rigidity fixing means for fixing the position of the divided permanent magnet in the circumferential direction is such that the motor has a harmonic component of the electromagnetic force of the pole number p and the spatial order k and the spatial distribution mode is m = (p × k) / 2, and the number of constraints L ≠ (2 / n) × m
(Where n = 1, 2,..., N; N ≦ m).

The high rigidity fixing means for fixing the position of the divided permanent magnets in the circumferential direction is, specifically, a rib extending in the rotation axis direction and fixed to the inner surface of the outer peripheral wall, and extending in the rotation axis direction. It is realized as an integrally formed rib with the inner surface of the outer peripheral wall protruding.

The high rigidity fixing means for fixing the circumferential position of the divided permanent magnet includes a holding plate for aligning and holding the permanent magnet and a means for fixing the holding plate at the position on the outer peripheral wall. You may comprise.

In this case, the means for fixing the holding plate at the position on the outer peripheral wall is any of rivets, bolts, and welding.

According to another aspect of the present invention, there is provided an elevator for raising and lowering a car and a counterweight suspended from a rope hung on a sheave of a hoist driven by a motor along a guide rail. The present invention proposes an elevator in which the motor is any of the above-described everted permanent magnet motors.

According to the present invention, the rigidity of the ring vibration generating member caused by the electromagnetic force is adjusted, the resonance between the harmonic component space mode of the electromagnetic force and the ring vibration mode of the mechanical structure is avoided, and the vibration of the motor is reduced. Reduce noise.

The principle of the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating an example of the ring vibration mode. FIG. 2 is a view developed in the circumferential direction for easy understanding of the ring vibration mode. FIG. 3 is a chart showing the relationship between the number of constraints L and the order m of the ring vibration mode.

FIG. 2A shows zero-order, first-order, second-order, and third-order ring vibration modes generated when the rigidity is constant without any constraint in the circumferential direction. If the stiffness is constant, in principle,
All other ring vibration modes appear. Thus, when the time order, that is, the frequency at which the spatial distribution of the harmonic component of the electromagnetic force occurs coincides with the frequency of the generation of the annular vibration mode, a resonance phenomenon is caused, and excessive vibration and noise are generated. As described above, when there are many harmonic vibration components of the electromagnetic force system and the ring vibration mode of the mechanical structure, the structure having no constraint point in the circumferential direction easily resonates. In particular, such a phenomenon increases when the operating frequency range is wide as in the case of inverter-driven equipment.

Therefore, the ring vibration mode is restricted by increasing the rigidity at an arbitrary position in the circumferential direction. Hereinafter, for the sake of simplicity, the expression “constrain” is used instead of “increase rigidity”. The number of restraining positions for restraining the ring vibration mode is two. FIG. 2 (b),
(c) and (d) show low-order annular vibration modes that appear when the constraint number L is 2, 3, and 4. In the figure, white triangles represent constraints, and black triangles at both ends represent the same position on the circumference. In these cases, it can be seen that the node of the ring vibration mode is a node at the constrained position, as compared with the case of FIG. That is, “constraint” means forcing the annular vibration mode into a node. Further, as the number of constraints L increases, the number of generated ring vibration modes decreases, and the order thereof generally tends to increase. Further, the generated annular vibration mode differs depending on the constraint number L. When the relationship between the constraint number L and the ring vibration mode order m is arranged,
As shown in FIG. 3, it is obtained by the following equation.

[0022]

(Equation 1)

The vibration or noise generated by the electromagnetic force causes a resonance phenomenon when the spatial distribution of the harmonic components of the electromagnetic force and the annular vibration mode shown in FIG. 3 occur at the same frequency, and increases. The following relationship is established between the annular vibration mode m of the mechanical structure, the pole number P of the electromagnetic force, and the harmonic space order k.

[0024]

(Equation 2)

For this reason, in order to reduce the vibration and noise due to the electromagnetic force, a structure in which the number of constraints is blank in the relationship between the order m of the annular vibration mode and the number of constraints L in FIG. It will be good. The constraint point does not necessarily need to be located on the circumference in equal divisions, but may be restricted to the vicinity of the antinode of the mode of the annular vibration mode order to be restricted. For example, m = 2 generated at two constraint positions in FIG.
Assuming that three restraint positions shown in FIG. 2C are used to suppress the annular vibration modes 1 and 2, the restraint positions are at or near the antinode of each of the annular vibration modes. At least not near the nodes of each ring vibration mode. That is, between the constrained positions, it is necessary that annular vibration modes having the same distribution exist in the same phase or opposite phases.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, referring to FIGS.
An embodiment of an everting type permanent magnet motor according to the present invention will be described.

<< Embodiment 1 >> FIG. 4 is a longitudinal sectional view showing a schematic structure of Embodiment 1 of an everted permanent magnet motor according to the present invention. FIG. 5 is a cross-sectional view showing the structure of the outer peripheral wall of the permanent magnet mounting portion and a part of the armature of the external rotation type permanent motor of FIG. 4 in a plane perpendicular to the rotation axis. FIG. 6 is a diagram showing the inner surface of the outer peripheral wall of the everted permanent motor shown in FIG.

The external permanent magnet motor 1 comprises a rotor 2 and a stator 3. The rotor 2 has an outer peripheral wall 21 holding a permanent magnet 220 for generating rotation by a rotating magnetic field.
, An end plate 22, a rotating shaft 24, and a boss 23 rigidly connected to the rotating shaft 24 by shrink fitting or the like to connect the end plate 22 and the rotating shaft 24. The stator 3 is an armature 3
1 and a frame 32. Rotary shaft 24 of rotor 2
Are supported by bearings 25 fixed to the stator 3. The frame 32 of the stator 3 is fixed to a foundation 33. If no countermeasures are taken, the outer peripheral wall 21 of the rotor 2
In this case, large vibrations and noises are generated when the electromagnetic force of the harmonic acts in the circumferential direction and its spatial order resonates with the annular vibration mode of the outer peripheral wall 21.

5 and 6, a permanent magnet 220 is provided inside the outer peripheral wall 21 between the joint 212 with the end plate 22 and the opening 211 along the direction of the rotating shaft 24.
Are installed separately. A holding plate 223 for preventing the permanent magnet 220 from falling off and ribs 221 and 222 for keeping the permanent magnet aligned are provided. It is preferable that the holding plate 223 be integrated with the ribs 221 and 222 by welding or screw connection. The ribs 221 and 222 are rigidly connected and fixed to the inside of the outer peripheral wall 21 by welding, screw connection, or the like. The ribs 222 have higher rigidity than the ribs 221 and can be arranged according to the reference in FIG. That is, the number of ribs 222 having increased rigidity is determined according to the blank portion in FIG. Generally, when the order of the annular vibration mode of the outer peripheral wall 21 of the rotor 2 is m, the number of ribs having high rigidity is determined so as to satisfy the following equation.

[0030]

(Equation 3)

Specifically, the harmonic component of the electromagnetic force is
If it is remarkably present at the next time, large vibration and noise will be generated when resonating with the sixth mode of the annular vibration of the mechanical structure. In this case, the constraint number L is 2, 3, 4,
If the number is set to 6, 12, the generation of the ring vibration mode is made obvious, and the effect is reversed. On the other hand, when the number of constraints L is 5, 7,
8, 9,..., The sixth mode of annular vibration does not occur, so that resonance can be avoided and vibration and noise can be suppressed. Even in the case where a large number of spatial distributions of harmonic components of the electromagnetic force are included, if the constraint number L is selected in the same manner, resonance with the mechanical structure can be avoided, and vibration and noise can be suppressed.

In the first embodiment, the ribs 221 and 222 are separated from the connecting portion 212 between the end plate 22 and the outer peripheral wall 21.
3, the reinforcing portion 213 is formed in the circumferential direction of the opening to further increase the ring rigidity, and the ribs 221 and 222 are arranged as shown in FIG. May be arranged as follows.

In the first embodiment, the ribs 221 and 222 are separated from the connecting portion 212 between the end plate 22 and the outer peripheral wall 21.
Is arranged up to the opening at the other end of the rib, but the rib 2 having low rigidity
21 does not need to contribute to the ring rigidity,
A length or position that only serves to maintain the alignment of the permanent magnets may be used.

Instead of arranging the ribs with increased rigidity as separate members, if the required rigidity can be secured, it is also possible to adopt integrally formed ribs with the inner surface of the outer peripheral wall protruding.

In implementing the present invention, if the spatial distribution of the harmonic component of the electromagnetic force is determined in advance, if the electromagnetic force of the spatial distribution is large and the frequency band is in the audible range, FIG. According to 2, the arrangement structure of the ribs 222 having increased rigidity can be designed. That is, if FIG. 3 or equation (2) is stored in a computer in advance, the spatial mode calculation result of the harmonic component of the electromagnetic force indicates the arrangement of the ribs 222 having increased rigidity to suppress the vibration and noise of the motor. Can be automatically determined.

FIG. 7 is a flowchart showing an example of a processing procedure for determining the number of ribs 222 having increased rigidity necessary for avoiding resonance when a natural frequency or a natural mode is obtained at the time of designing a mechanical structure system. It is.

Step 102: Spatial mode order, frequency, amplitude,
The phase angle and the inner diameter and length of the rotor and the stator are input.

Step 103: Based on these input data, an exciting force (unit is force) that matches the structural finite element data and coordinates from the amplitude and phase corresponding to the spatial order of the harmonic component of the electromagnetic force. Performs a conversion to.

Step 105: The frequency of the electromagnetic force harmonic component is compared with the natural frequency of the mechanical structure.
It will be the object of the subsequent calculation.

Step 106: The resonance determination value SMORC is calculated from the natural mode of the natural frequency corresponding to the determined frequency and the spatial mode of the electromagnetic force. The calculation at this time is as follows. If the electromagnetic force spatial mode is ｛φe and the eigenmode of the structural vibration of the motor is ｛φs, the resonance determination value
Is obtained by the following equation.

[0041]

(Equation 4)

This coefficient indicates the direction cosine of the two vectors. That is, it approaches 1 when the two vectors are in the same direction, and approaches 0 when there is no correlation. Therefore, the mechanical vibration due to the electromagnetic force tends to increase as the coefficient is closer to 1, and the mechanical vibration is not excited as the coefficient is closer to 0.

Step 107: In response to the screen display command,
Display the calculation result.

FIG. 8 is a view showing an example of the display of the calculation result by the processing procedure of FIG. In FIG. 8, the resonance determination value SMORC (Space Mode Resonance) is set using the spatial mode order of the electromagnetic force and the natural frequency of the mechanical structure as parameters.
Criteria) is displayed three-dimensionally in a bar graph.
When SMORC is large, the electromagnetic force is in resonance with the natural frequency of the mechanical structure, and vibration and noise increase. On the other hand, when SMORC is small, the electromagnetic force is almost uncorrelated with the natural frequency of the mechanical structure, and the vibration amplitude and noise are also small. If the answer is obtained by changing the number of ribs arranged, the optimum arrangement of the ribs with increased rigidity can be determined.

Embodiment 2 FIG. 9 shows the structure of the outer peripheral wall of the permanent magnet mounting portion and a part of the armature of the external rotation type permanent magnet motor according to the present invention in a plane perpendicular to the rotation axis. It is sectional drawing. FIG. 10 is an enlarged view showing a part of the structure of FIG. FIG. 11 is a diagram showing a state where the structure of FIG. 10 is viewed from the inside of the outer peripheral wall. The schematic configuration of the external rotation type permanent magnet motor is the same as that of the first embodiment shown in FIG. Permanent magnet 22
No. 0 is prevented from dropping from the inside of the outer peripheral wall by the rivet 210a and the holding plate 210b. As shown in FIG. 11, a connecting portion 212 between the outer peripheral wall 21 of the rotor 2 and the end plate 22 is provided.
By disposing the rivets at at least two places from the opening toward the opening 211, the circumferential displacement of the permanent magnet can be prevented. In addition, the permanent magnets 220 are connected in the circumferential direction by the holding plate 210b, so that the rigidity of the outer peripheral wall 21 against the annular vibration can be increased. Further, the stopper 224
Accordingly, it is possible to prevent the displacement toward the opening 211 side. This means that the natural frequency of the vibration of the mechanical structure of the outer peripheral wall 21 can be increased with respect to the excitation frequency corresponding to the harmonic component of the electromagnetic force, and resonance in the operating region can be avoided. As a result, vibration and noise due to the electromagnetic force generated from the outer peripheral wall 21 can be reduced.

In the second embodiment, the holding plate 210b is connected to the outer peripheral wall 21 using the rivets 210a. However, the holding plate 210b can be fixed with bolts without using the rivets 210a, and can be directly connected by welding or the like. .

In the second embodiment, the holding plate 210b is divided into a plurality in the circumferential direction so as to connect the permanent magnets 220 two by two. A holding plate can also be used.

<< Embodiment 3 >> FIG. 12 employs an everting type permanent magnet motor according to the present invention, does not have a machine room, and includes a car, an everting type permanent magnet motor, a hoist and the like in the hoistway. FIG. 1 is a perspective view showing an entire structure of an embodiment of an elevator installed in an elevator. In FIG. 12, the hoistway is formed so as to be surrounded by a wall or the like. This hoistway bottom 5
5 is a motor 1 of an abduction type permanent magnet motor according to the present invention.
A hoist 6 connected to the hoist 6 is disposed, and a car 58 guided by a guide rail 33 is suspended from a rope 56 hung on a sheave 60 driven by the hoist 6, and the rope 56 Has a guide rail 3
The counterweight 51 guided by 4 is hung. In the elevator configured as described above, when the hoist 6 is driven by the everted permanent magnet motor 1 according to the present invention, the car 58 suspended by the rope 56
Moves up and down in the hoistway and back and forth between predetermined floors as requested by passengers.

In this example, an elevator adopting a so-called 2: 1 roping is illustrated, in which both ends 50 of the rope 56 are fixed, and several pulleys 27, 29, 32 are used. Basket 58 on both ends of the rope
The present invention can also be applied to an elevator employing 1: 1 roping in which the counterweight 51 is suspended.

The position of the epimotor permanent magnet motor 1 according to the present invention and the hoist 6 connected thereto are not limited to the hoistway bottom 55 of the present embodiment, but may be any position in the hoistway. It may be a position.

Further, even if the present invention is applied to an elevator having a machine room above a hoistway, vibration and noise due to electromagnetic force generated from the outer peripheral wall 21 can of course be reduced.

In the third embodiment, since the external rotation type permanent magnet motor according to the present invention of the first or second embodiment is employed, no annular vibration mode is generated. Noise can be suppressed. Even when a large number of spatial distributions of the harmonic components of the electromagnetic force are included, resonance with the mechanical structure can be avoided, and vibration and noise can be suppressed. Therefore, even if all of the car, the epicyclic permanent magnet motor, the hoist, etc. are installed at the bottom 55 in the hoistway without having a machine room, the rider can start riding from the epicyclic permanent magnet motor 1 in the hoistway. Vibration and noise transmitted to the car 58 or the landing floor (not shown) are suppressed, and a compact and comfortable elevator can be realized.

[0053]

According to the present invention, the position for avoiding the resonance between the harmonic component of the electromagnetic force due to the stator winding and the annular vibration of the mechanical structure of the motor and preventing the circumferential displacement of the permanent magnet is prevented. Since the high-rigidity means for fixing the circumferential position of the divided permanent magnet is provided, vibration and noise generated by the electromagnetic force of the motor can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a ring vibration mode.

FIG. 2 is a diagram developed in a circumferential direction for easy understanding of a ring vibration mode.

FIG. 3 is a table showing a relationship between a constraint number L and an order m of an annular vibration mode.

FIG. 4 is an embodiment of an everting type permanent magnet motor according to the present invention.
It is a longitudinal cross-sectional view which shows the schematic structure of.

FIG. 5 is a cross-sectional view showing the structure of an outer peripheral wall of a permanent magnet mounting portion and a part of an armature of the external rotation type permanent motor of FIG. 4 in a plane perpendicular to a rotation axis.

FIG. 6 is a developed view showing the inside of the outer peripheral wall of the everted permanent motor of FIG. 4;

FIG. 7 is a flowchart illustrating an example of a processing procedure for determining the number of ribs having increased rigidity necessary for avoiding resonance when a natural frequency or a natural mode is determined at the time of designing a mechanical structure system.

8 is a diagram showing an example of a display of a calculation result according to the processing procedure of FIG. 7;

FIG. 9 shows a second embodiment of an epicyclic permanent magnet motor according to the present invention.
FIG. 5 is a cross-sectional view showing the structure of the outer peripheral wall of the permanent magnet mounting portion and part of the armature in a plane perpendicular to the rotation axis.

FIG. 10 is an enlarged view showing a part of the structure of FIG. 9;

11 is a diagram showing a state where the structure of FIG. 10 is viewed from the inside of the outer peripheral wall.

FIG. 12 shows an embodiment of an elevator employing an everting type permanent magnet motor according to the present invention, having no machine room, and having a car, an everting type permanent magnet motor, and a hoist all installed in a hoistway. It is a perspective view which shows the whole structure of.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Rotor 3 Stator 6 Hoist 21 Outer peripheral wall 22 End plate 23 Boss 24 Rotating shaft 25 Bearing 31 Armature 32 Frame 33 Foundation 34 Stator tooth part 50 Fixed ends 52 of rope 56 51 Counterweight 52 Pulley 53 Car guide rail 54 counterweight guide rail 55 hoistway bottom 56 rope 57 pulley 58 car 59 pulley 60 hoist sheave 210a rivet 210b holding plate 213 reinforcing portion 220 permanent magnet 221 rib 222 high rigidity rib 223 holding plate 224 stopper

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideki Nihei 1070 Ma, Hitachinaka City, Ibaraki Prefecture Inside the Mito Plant of Hitachi, Ltd. F-term (Reference) 3F306 AA12 AA13 BA00 BA07 5H621 AA04 BB07 GA01 GA04 HH05 JK08 5H622 CA02 CA05 CA10 CB03 PP04 PP05 PP14 PP15 PP17

Claims (7)

[Claims] 1. A stator comprising a stator winding and a cylindrical rotor having a rotating shaft supported coaxially with the stator and having a permanent magnet divided circumferentially inside an outer peripheral wall. In the abduction type permanent magnet motor, in a position to avoid a resonance between a harmonic component of an electromagnetic force by the stator winding and an annular vibration of a mechanical structure of the motor and to prevent a circumferential displacement of the permanent magnet. An everted permanent magnet motor, comprising: high rigidity fixing means for fixing the circumferential position of the divided permanent magnet. 2. The permanent magnet motor according to claim 1, wherein said rigid means for fixing the position of said divided permanent magnets in the circumferential direction comprises: It has a harmonic component of the k-th electromagnetic force, and the spatial distribution mode is m = (p
× k) / 2, and are arranged in the circumferential direction of the outer peripheral wall so as to satisfy the constraint number L ≠ (2 / n) × m (where n = 1, 2,..., N; N ≦ m). An abduction type permanent magnet motor. 3. The permanent magnet permanent magnet motor according to claim 1, wherein said high rigidity fixing means for fixing a position of said divided permanent magnet in a circumferential direction extends in said rotation axis direction. An everting type permanent magnet motor, characterized in that it is a rib fixed to the inner surface of the outer peripheral wall. 4. The external rotation type permanent magnet type motor according to claim 1, wherein the high rigidity fixing means for fixing a circumferential position of the divided permanent magnet extends in the rotation axis direction. An abduction type permanent magnet motor characterized by being an integrally formed rib with an inner surface of an outer peripheral wall protruding. 5. The external permanent magnet type motor according to claim 1, wherein a high rigidity fixing means for fixing a position of the divided permanent magnet in a circumferential direction holds and aligns the permanent magnet. An abduction type permanent magnet motor, comprising: a holding plate; and means for fixing the holding plate at the position on the outer peripheral wall. 6. The motor according to claim 5, wherein the means for fixing the holding plate at the position on the outer peripheral wall is any one of rivets, bolts, and welding. Abduction type permanent magnet type motor. 7. An elevator for raising and lowering a car and a counterweight suspended from a rope hung on a sheave of a hoist driven by a motor along a guide rail, wherein the motor comprises: An elevator, which is the epicyclic permanent magnet motor according to any one of the preceding claims.