WO2003052901A1 - Permanent magnet type motor and elevator device - Google Patents

Abstract

The motor (23) of a hoist is equipped with a rotor core (33) having incorporated therein permanent magnets (37) for forming magnetic poles. The inner peripheral surface of each magnetic pole of the rotor core (33) is convex so that a gap between it and a stator core (26) is smaller in the vicinity of the center of the magnetic pole and larger in the peripheral opposite ends. More specifically, of the inner peripheral surface of each magnetic pole, the central portion is a planar portion (33a) and the peripheral opposite ends are arcuate surface portions (33b). As a result, the magnetic flux distribution between the rotor core (33) and the stator core (26) approximates closely to a sine wave form, reducing the cogging torque.

Description

 Specification

 Permanent magnet motor and elevator device

 Technical field

 The present invention relates to a permanent magnet type motor, and more particularly to a permanent magnet type motor suitable for being incorporated into a hoist of an elevator apparatus and an elevator apparatus using the permanent magnet type motor.

 Background art

 Fig. 1 shows an example of a conventional permanent magnet type motor. This mode is, for example, a brushless motor with three phases and 20 poles, and the outer periphery of the stator 1 (only the stator core 2 is shown in FIG. 1 and the stator winding is omitted). The rotor 3 rotatably disposed in the portion is configured such that a plate-shaped permanent magnet 6 is inserted into a through hole 5 provided in a portion of the rotor iron core 4 where each magnetic pole is formed. Each permanent magnet 6 is magnetized in the radial direction so that the S pole and the N pole are alternately located in the circumferential direction.

 In this case, the gap size between the rotor core 4 and the stator core 2 is configured to be constant over the entire circumference. For this reason, the change in the magnetic resistance due to the rotation angle becomes small, and the magnetic flux density distribution in the gap between the iron cores depends on the arrangement of the permanent magnets 4.

Therefore, as shown in FIG. 2, the magnetic flux density distribution has a trapezoidal wave shape, and the magnetic flux density greatly changes depending on the rotation angle (mechanical angle). That is, since the cogging torque is increased, the torque ripple is increased, and the motor efficiency is reduced, and the vibration and the noise are increased.

 Therefore, a first object of the present invention is to provide a permanent magnet type motor capable of reducing vibration and noise by reducing cogging torque and torque ripple, and a second object is to provide vibration and noise. The aim is to provide a comfortable and comfortable elevator device.

 Disclosure of the invention

A permanent magnet type motor according to the present invention includes: a stator having a stator core on which a stator winding is wound; and a permanent magnet for magnetic pole formation, which is disposed on an outer peripheral portion of the stator. A permanent magnet type motor having a rotor having a rotor core in which a magnet is incorporated. The magnetic pole is characterized in that it is formed in a flat or convex shape so that the center of the magnetic pole is smaller than both ends in the circumferential direction.

 According to the above configuration, the magnetic flux density distribution in the air gap between the stator core and the rotor core approximates a sinusoidal shape, so that the cogging torque can be reduced and the torque ripple can be reduced.

 In this case, as the shape of the inner peripheral surface of each magnetic pole of the rotor core, it is preferable that the central portion in the circumferential direction is formed in a planar shape, and both ends in the circumferential direction are formed in an arc shape.

In addition, the center part in the circumferential direction of the inner circumferential surface of each magnetic pole of the rotor core is formed in a flat shape, and both ends in the circumferential direction are formed in a flat shape inclined from the center part to the end part toward the outer circumferential part. It is also a good configuration. Further, the inner peripheral surface of each magnetic pole of the rotor core may be formed in an arc shape.

 Also provided are a stator having a ring-shaped stator core having a plurality of teeth protruding toward the center, a stator having a stator winding wound around each tooth, and a rotor having a permanent magnet therein. In an inner-open-and-close type motor in which the rotor is rotated by generating a magnetic field by passing a current through the stator winding, an outer peripheral surface of the rotor core facing the teeth is eternal. The teeth are formed so that the distance between the outer peripheral surface corresponding to the circumferential center of the magnet and the teeth is shorter than the distance between the outer peripheral surface corresponding to the circumferential ends of the permanent magnet and the teeth. This is a characteristic feature.

 Further, the permanent magnet is inserted into a through hole provided in the rotor, and the through hole penetrates through the through hole more than a distance between a circumferential central portion of the through hole and an outer peripheral surface of the rotor core. The motor is characterized in that a distance between a circumferential end of the hole and an outer peripheral surface of the rotor core is reduced. Further, the motor is characterized in that an air gap is formed between a circumferential end of the permanent magnet and the spiral core.

A ring-shaped stator core having a plurality of teeth projecting radially from the center, and a stator having a stator winding wound around each tooth; A rotor having a permanent magnet therein, wherein the rotor is rotated by passing a current through the stator winding to generate a magnetic field, and the rotor faces the teeth. The inner peripheral surface of the rotor core has a distance between the inner peripheral surface corresponding to the circumferential center of the permanent magnet and the teeth, and the inner peripheral surface corresponding to the peripheral end of the permanent magnet and the teeth. It is characterized by being formed to be shorter than the distance between

 In addition, the elevator apparatus of the present invention further includes a cage provided so as to be able to move up and down in the hoistway, a weight mounting portion that is provided so as to be able to move up and down in the hoistway, and having a count weight. It is characterized by having a winding machine having a permanent magnet type motor.

 According to the above configuration, the cogging torque of the permanent magnet type motor, which is the driving source of the hoist, can be reduced, so that the generation of vibration and noise can be suppressed, and the riding comfort is improved.

 In this case, it is preferable that the hoist be provided at the weight mounting portion. According to such a configuration, since the hoisting machine itself functions as a weight, the amount of the counterweight mounted on the weight mounting portion can be reduced. Also, since there is no need to provide a machine room for installing the hoisting machine above the hoistway, the height of the building can be reduced accordingly. In the present invention, the “rotor having at least two plate-shaped permanent magnets therein” means that at least one side surface of the permanent magnet is not exposed.

 BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a partial sectional view of a conventional permanent magnet type motor.

 FIG. 2 is a diagram showing a magnetic flux density distribution in a gap between iron cores of the permanent magnet type motor shown in FIG.

 FIG. 3 shows the first embodiment of the present invention, and is a partial plan view of a permanent magnet type motor.

 Fig. 4 is a vertical sectional side view of the hoist of the elevator.

 FIG. 5 is a perspective view showing the overall configuration of the elevator apparatus.

Fig. 6 shows the magnetic flux density distribution in the air gap between the cores of the permanent magnet type motor shown in Fig. 3. FIG.

 FIG. 7 is a diagram for explaining the relationship between the shape of the inner peripheral surface of each magnetic pole of the rotor core and the magnetic flux density distribution, and shows a permanent magnet type motor when the entire inner peripheral surface is configured to be planar. Evening partial plan view.

 FIG. 8 is a view showing a magnetic flux density distribution in a gap between iron cores of the permanent magnet type motor shown in FIG. 7.

 FIG. 9 is a diagram for explaining the relationship between the shape of the inner peripheral surface of each magnetic pole of the rotor core and the magnetic flux density distribution, and shows a permanent magnet type motor in which the entire inner peripheral surface is formed in an arcuate shape. Evening partial plan view.

 FIG. 10 is a diagram showing a magnetic flux density distribution in a gap between iron cores of the permanent magnet type motor shown in FIG. 9;

 FIG. 11 shows a second embodiment of the present invention and is a partial plan view of a permanent magnet type motor.

 FIG. 12 is a diagram showing a magnetic flux density distribution in a gap between iron cores of the permanent magnet type motor shown in FIG. 11;

 FIG. 13 is a partial plan view of a permanent magnet motor according to a third embodiment of the present invention. FIG. 14 is a partial plan view of a permanent magnet motor according to a modification of the third embodiment of the present invention.

 FIG. 15 is a schematic configuration diagram showing an example in which the present invention is applied to a motor with a single bite of a thinner type.

 Embodiment of the Invention

 Hereinafter, a first embodiment in which the present invention is applied to a hoist of an elevator apparatus will be described with reference to FIGS. 3 to 10. First, Fig. 5 shows the schematic configuration of the elevator device. In FIG. 5, in a hoistway 11, a car 12 and a weight mounting portion 13 are configured to move up and down along first and second guide rails 14 and 15, respectively. I have. Two moving pulleys 16 are fixed to the lower part of the car 12.

In addition, a hoisting machine 17 is disposed above the weight mounting portion 13, and a count weight 18 is mounted below. The hoisting machine 17 It is housed in a case 13a provided above the weight mounting part 13.

 On the other hand, an intermediate pulley 19 is installed near the top of the hoistway 11, and a rope 20 is hooked on the intermediate pulley 19. One end of the rope 20 is fixed near the top of the first guide rail 14, and the other end is fixed near the top of the second guide rail 15. The cage 12 is supported between the one end of the rope 20 and the intermediate pulley 19 via the moving pulley 16. Further, between the other end of the rope 20 and the intermediate pulley 19, the weight mounting portion 13 is provided via the sheave 21 of the hoisting machine 17 (see FIG. 4). It is supported so that it can move up and down.

 On the other hand, as shown in FIG. 4, the hoisting machine 17 has a rectangular plate-shaped support plate 22 and a brushless motor 23 that directly rotates and drives the sheave 21. Is configured. The support plate 22 has a circular opening 22a at the center thereof, and a substantially cylindrical sleeve extending rightward in FIG. 4 is provided at the periphery of the opening 22a. 24 are fixed. A stator 25 of the motor 23 is fixed to an outer peripheral portion of the sleeve 24. The stator 25 includes a stator core 26 made of laminated silicon steel plates, and a coil 27 wound around the stator core 26.

 In this case, the stator core 26 has, for example, 63 teeth 26a and slots 26b (all shown only in FIG. 3). In the slot 26b, 30 coils 27 (therefore, each of the U-phase, V-phase, and W-phase coils has no more than 10 coils) so as to form a distributed winding forming one coil at a 3-slot pitch. ) Is stored. At this time, the U-phase, V-phase, and W-phase are arranged so that each coil 27 is shifted by one slot.

A rotor 29 is rotatably supported on an inner peripheral portion of the sleeve 24 via a ball bearing 28. The rotor 29 includes a cylindrical shaft portion 30 fitted to the inner ring 28 a of the ball bearing 28, and a disk-shaped base integrally formed on the right end of the shaft portion 30. Part 31, a cylindrical yoke part 32 integrally formed with the peripheral part of the base part 31, and fixed to the inner peripheral part of the yoke part 32 And a rotor iron core 33 made of laminated steel sheets. A bearing holder 34 for supporting the inner ring 28 a of the ball bearing 28 is attached to the left end of the shaft 30.

 Further, a mounting shaft 21 a of the sheave 21 is inserted into the shaft 30 of the rotor 29. A key 35 is inserted between the shaft portion 30 and the mounting shaft portion 21a, and the rotor 29 and the sheave 21 are integrally rotated by the key 35. It is configured as follows. In addition, a plurality of grooves 21b are formed in the outer periphery of a portion of the sheave 21 protruding leftward in FIG. 4 from the shaft portion 30, and the groove 21b is formed in the groove 21b. Rope 20 is hooked.

 Now, the configuration of the rotor 29 will be described with reference to FIG. As shown in FIG. 3, for example, 20 trapezoidal through holes 36 are formed inside the rotor core 33, and each of the through holes 36 has a rectangular plate shape. A permanent magnet 37 for forming a magnetic pole is accommodated and fixed. Each of the permanent magnets 37 is magnetized in the radial direction, and is arranged such that the S pole and the N pole are alternately located in the circumferential direction. At this time, the permanent magnet 37 is not located at both ends in the circumferential direction of the through hole 36, and is formed inside the rotor core 33 as a space 36a having a triangular cross section.

Further, in the present embodiment, the rotor core is arranged such that the gap between the rotor core 33 and the stator core 26 is smaller at the center of the magnetic pole than at both ends in the circumferential direction. The inner peripheral surface of each of the magnetic poles 33 is formed in a convex shape. In particular, in the present embodiment, of the inner peripheral surfaces of the magnetic poles of the rotor core 33, the central portion is formed into a flat shape (hereinafter, this portion is referred to as a flat portion 33a), and both ends in the circumferential direction are formed. It is configured as an arc surface (hereinafter, this portion is referred to as an arc surface portion 33b). Specifically, assuming that P is the center in the circumferential direction of the inner circumferential surface of the magnetic pole, Q is the end in the circumferential direction, and R is the boundary between the plane portion 33a and the arc surface portion 33b, the center P and the rotor The angle <1 between the plane that connects the rotation center of the rotor 9 and the plane that connects the boundary R and the rotation center of the rotor 29 is about 5 °, such as the rotation center of the boundary R and the rotor 29. The angle 0 2 between the plane connecting the end and the plane connecting the end It is set to about 4 °.

 The center of the arcuate surface portion 33b is on an extension surface extending outward from the boundary R in a direction perpendicular to the flat surface portion 33a, and the distance is (2? Rr xn / 360 X2 to 27Trxn / 360). Note that η is the number of poles (η = 20 in this embodiment), and r is the radius of the rotor 29.

 Here, the reason why the inner peripheral surface of each magnetic pole of the rotor core 33 is formed in the above-described shape will be described below.

 As described in the Background Art section, if the gap size between the rotor core and the stator core is constant, the magnetic flux density distribution formed in the gap between the cores becomes a rectangular wave shape, so cogging occurs. The torque increases and the torque ripple increases. In order to find the shape of the inner peripheral surface of the rotor core 33 such that the magnetic flux density distribution in the air gap between the cores approximates a sinusoidal shape, the inventor conducted a magnetic flux analysis on various models of the shape. Then, the magnetic flux density distribution in the gap between the iron cores was estimated. FIG. 7 shows an example of a model. In this model, the entire inner peripheral surface of each magnetic pole of the rotor core 33 is formed in a planar shape. Fig. 8 shows the magnetic flux density distribution in the air gap between the iron cores in this model. As is clear from Fig. 8, the magnetic flux density distribution approximates a sinusoidal shape.

 FIG. 9 shows another example of the model. In this model, the entire inner peripheral surface of each magnetic pole of the rotor iron core 33 is formed in an arc shape. FIG. 10 shows the magnetic flux density distribution in the air gap between the iron cores in this model. In this case, the radius of the arc surface is set to (2τΤΓΧη / 360X2 ~ 27rr xn / 360). As is clear from FIG. 10, the magnetic flux density distribution approximates a sine wave shape.

Comparing FIG. 8 with FIG. 10, the height of the top of the magnetic flux density distribution (that is, the magnitude of the magnetic flux density when the mechanical angle is 9) is lower in FIG. That is, in the model of FIG. 7, the change in the magnetic flux density near the center of each magnetic pole of the rotor core 33 (that is, the mechanical angle is around 9 °) is smaller. On the other hand, looking at the magnetic flux density distribution near both ends in the circumferential direction, there is a part where the model in Fig. 7 changes significantly compared to the model in Fig. 9. Therefore, the inventor of the present invention has A model was constructed in which the area around the center was a flat surface and both ends in the circumferential direction were arc-shaped. In this case, assuming that the proportion occupied by a flat portion (that is, the flat portion 33a) with respect to the inner peripheral surface of each magnetic pole of the rotor core 33 is m, the angle 0 1 of the flat portion 33a is expressed by the following equation. It is represented by

 θ 1 = {(366 / n) X (m / 2)} °

 Here, 01 is shown as an angle from the circumferential center P of the magnetic pole to one boundary R. Therefore, the angle range of the actual plane part 33 a is twice as large as 0 1.

 Although not specifically shown, as a result of the magnetic flux analysis with m set to various values, when m = 0.56, that is, as described above, 0 1 is about 5. When it was set to, it was found that the magnetic flux density distribution in the air gap between the iron cores could be made very close to a sine wave shape. Fig. 6 shows the magnetic flux density distribution at this time. In this way, by keeping the magnetic flux density distribution close to a sine wave shape and by supplying a three-phase sine wave current to the three-phase winding wound around each tooth, the rotational torque is ideally kept constant. The cogging torque can be reduced to zero. According to the analysis results, the cogging torque is reduced by 50% and the tonnage ripple is reduced by 40% in the motor 23 of this embodiment as compared with the conventional motor.

 According to this embodiment, the shape of each magnetic pole of the rotor core 33 is configured so that the magnetic flux density distribution in the air gap between the cores approximates a sine wave shape, so that cogging torque is reduced and torque ripple is reduced. Reduction can be achieved. Therefore, in the present embodiment, by configuring the hoisting machine 17 of the elevator apparatus by the motor 23, vibration and noise generated when the hoisting machine 17 is driven can be suppressed. Because it is possible, riding comfort is improved.

 In particular, in the present embodiment, since the hoisting machine 17 is provided in the weight mounting portion 13, it is not necessary to provide a dedicated machine room near the top of the hoistway 11. In addition, there is also an effect that the amount of the counterweight 18 provided in the eight mounting portion 13 can be reduced.

FIGS. 11 and 12 show a second embodiment of the present invention, and the differences from the first embodiment will be described. The same parts as in the first embodiment are the same. One symbol is attached. That is, in the second embodiment, of the inner peripheral surface of each magnetic pole of the rotor core 33, both ends in the circumferential direction are formed into inclined surfaces (hereinafter, this portion is referred to as an inclined surface portion 33 c). Make up. In this case, the inclined surface portion 33c is formed in a planar shape connecting the boundary R and the end Q shown in the first embodiment.

 FIG. 12 shows the magnetic flux density distribution in the air gap between the iron cores at this time. As is clear from the comparison between FIG. 12 and FIG. 6, also in this case, a magnetic flux density distribution very similar to a sine wave shape can be obtained.

 Further, when the both ends in the circumferential direction of the inner peripheral surface of the rotor core 33 are formed as the inclined surfaces 33c, there is an advantage that the manufacture is easier as compared with the case where the arc surfaces 33b are formed. It should be noted that the present invention is not limited to the above-described embodiment, and can be modified or expanded as follows, for example.

 The hoisting machine may be arranged in a machine room provided near the top of the hoistway. In this case, a car is connected to one end of each of the plurality of ropes hung on the sheave of the hoist, and a wire mounting unit is connected to the other end. Then, when the hoist is driven to rotate the sheave, the car and the weight mounting portion are moved up and down.

 The ratio m occupied by the plane portion in the inner peripheral surface of each magnetic pole of the rotor core is not limited to 0.56, but may be any value as long as 0≤m≤1 is satisfied. Therefore, the entire inner peripheral surface of each magnetic pole may be flat, or the entire inner peripheral surface of each magnetic pole may be arcuate.

 That is, if m satisfies 01, the magnetic flux density distribution in the air gap between the iron cores can be made sufficiently close to a sine wave shape, and cogging torque and torque ripple can be reduced.

 Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 13 shows a partial plan view of the permanent magnet type motor 40 according to the present embodiment. Here, portions having the same functions as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the first embodiment, the inner peripheral surface of the rotor core 33 and the stator core 26 (teeth 26a and a slot 26b). In this embodiment, the inner peripheral surface 42 of the rotor core 33 and the through hole into which the permanent magnet 37 is inserted are further provided. It is characterized by the distance from the hole 36.

 That is, the distance between the circumferential end of the through hole 36 and the inner circumferential surface 42 of the rotor core 33 (indicated by a in FIG. 13) is greater than the distance between the circumferential end of the through hole 36 and the rotor. The distance between the core 33 and the inner peripheral surface 42 (indicated by X in FIG. 13) is shortened.

 As described above, the permanent magnet 37 is magnetized in the radial direction, but by adopting such a structure, the rotor between the permanent magnet 37 and the permanent magnet 37 exits from the N pole of the permanent magnet 37. The amount of magnetic flux passing through the core 33 and returning to the S pole of the permanent magnet can be reduced, and the effective magnetic flux can be increased.

 It is desirable that X be small, but in order to manufacture the rotor integrally, X cannot be set to zero, that is, the end of the permanent magnet cannot be exposed. In the case of manufacturing a rotor by laminating steel sheets punched through through holes 33a by press working, the limit of X is about the thickness of one steel sheet. Therefore, assuming that the thickness of the laminated steel sheet—b is b, the relationship between b, x, and a is b <x <a.

 Further, a modified example of the third embodiment will be described with reference to the drawings. FIG. 14 shows a partial plan view of a permanent magnet motor according to this modification. In this modification, the shape of the through-hole 36 formed in the rotor core 33 is characterized. That is, the through-hole 36 is made larger than the permanent magnet so that a gap 36a is formed at both ends in the circumferential direction when the permanent magnet 37 is inserted into the through-hole 36, and the gap is formed in the inner circumference of the rotor core 33. A through hole 36 is formed so as to approach the surface 40.

 As a result of such a structure, the magnetic flux of the magnetic flux that exits from the N pole of the permanent magnet 37, passes through the inside of the rotor core 33 between the permanent magnets 37, and returns to the S pole of the permanent magnet 37 The road can be made long and narrow. Accordingly, the magnetic resistance of this magnetic path increases, and the amount of magnetic flux passing through this magnetic path is further reduced, and as a result, the amount of effective magnetic flux can be increased.

In this embodiment, the shape of the gap 36a is trapezoidal in plan view. However, the present invention is not necessarily limited to this embodiment. As shown in the first embodiment, the rotor may have a triangular shape in which the rotor core side is the base, or may have other shapes. However, it is sufficient that the magnetic resistance of the magnetic path becomes larger as compared with the conventional example. Even in such a case, the amount of magnetic flux passing through the inside of the rotor core can be reduced.

 Further, in the present embodiment, the case where the rotor 33 is disposed outside the stator core 26 has been described as an example of a rotor-in-one-out type motor, but the rotor is provided inside the stator. The present invention may be applied to an inner bite-and-evening type mooring provided. An embodiment in this case is shown in FIG.

 As shown in this figure, in the inner bite-and-night mode, the outer peripheral surface 44 of the rotor core facing the teeth 26a corresponds to the outer peripheral surface 44 corresponding to the central part in the circumferential direction of the permanent magnet 37. The distance between the teeth 26a and the teeth 26a may be shorter than the distance between the outer peripheral surface 44 corresponding to the circumferential end of the permanent magnet 37 and the teeth 26a.

 Further, when the third embodiment is applied, the distance between the circumferential center of the through hole 36 into which the permanent magnet 37 is inserted and the outer peripheral surface 44 of the rotor core 26 is larger than the distance between the circumferential end of the through hole 36 and the circumferential end. If the distance between the rotor and the outer peripheral surface 44 of the rotor core 26 is reduced, the amount of effective magnetic flux can be increased.

 In addition, the present embodiment can be variously modified without changing the gist.

 According to the permanent magnet type motor of the present invention, the inner peripheral surface of each magnetic pole of the rotor core is such that the center of the magnetic pole is smaller than the both ends in the circumferential direction with respect to the gap size with the stator core. Because of the planar or convex configuration as described above, the cogging torque can be reduced and the torque ripple can be reduced, so that the motor efficiency can be improved and vibration and noise can be reduced.

 Further, according to the elevator apparatus of the present invention, by using a permanent magnet type motor capable of reducing cogging torque and torque, the hoist is configured to reduce vibration and noise and improve ride comfort. Can be.

Claims

The scope of the claims  1. A stator having a stator core on which a stator winding is wound, and a rotor core disposed on the outer periphery of the stator and having a permanent magnet for forming a magnetic pole incorporated therein. In a permanent magnet type motor with a rotor,  The inner peripheral surface of each magnetic pole of the rotor core is formed in a flat or convex shape such that the center of the magnetic pole is smaller than both ends in the circumferential direction with respect to the gap size with the stator core. A permanent magnet type motor characterized in that:  2. The inner peripheral surface of each magnetic pole of the rotor core, wherein the central portion in the circumferential direction is formed in a flat shape, and both ends in the circumferential direction are formed in an arc shape. Permanent magnet type module.  3. The central part in the circumferential direction of the inner peripheral surface of each magnetic pole of the rotor core is formed in a planar shape, and both ends in the circumferential direction are formed in a planar shape inclining from the central part to the end toward the outer peripheral part. 2. The permanent magnet type motor according to claim 1, wherein: 4. The permanent magnet type motor according to claim 1, wherein the inner peripheral surface of each magnetic pole of the rotor core is formed in an arc shape.  5. A stator having a 璟 -shaped stator core having a plurality of teeth protruding toward the center and a stator winding wound on each tooth, and a rotor having a permanent magnet therein. Wherein a current is passed through the stator winding to generate a magnetic field, and the rotor is rotated to rotate the rotor.  The outer peripheral surface of the rotor iron core facing the teeth, the distance between the outer peripheral surface corresponding to the circumferential central portion of the permanent magnet and the teeth, the outer peripheral surface corresponding to the circumferential end of the permanent magnet, It is formed to be shorter than the distance from the teeth.  6. The permanent magnet is inserted into a through-hole provided in the rotor, and the through-hole is larger than the distance between the circumferential center of the through-hole and the outer peripheral surface of the rotor core. 6. The motor according to claim 5, wherein a distance between a circumferential end of the through hole and an outer peripheral surface of the rotor core is reduced. 7. A gap is formed between the circumferential end of the permanent magnet and the rotor core. 6. The motor according to claim 5, wherein the motor is provided.  8. A ring-shaped stator core having a plurality of teeth projecting radially from the center, a stator having a stator winding wound around each tooth, and a rotor having a permanent magnet therein, In an outer rotor type motor in which the rotor is rotated by applying a current to the stator winding to generate a magnetic field,  An inner peripheral surface of the rotor core facing the teeth has a distance between an inner peripheral surface corresponding to a circumferential central portion of the permanent magnet and the teeth and an inner peripheral surface corresponding to a circumferential end of the permanent magnet. A molybdenum lens formed so as to be shorter than a distance between a surface and the teeth.  9. The permanent magnet is inserted into a through-hole provided in the rotor, and the through-hole is larger than a distance between a circumferential central portion of the through-hole and an outer peripheral surface of the rotor core. 9. The motor according to claim 8, wherein a distance between a circumferential end of the through hole and an outer peripheral surface of the rotor core is shorter. 10. The motor according to claim 8, wherein a gap is formed between a circumferential end of the permanent magnet and the rotor core.  11. A weight mounting portion having a counterweight provided to be able to move up and down in the hoistway, together with a car provided to be able to move up and down in the hoistway, and any one of claims 1 to 10. A hoisting machine having the permanent magnet type motor according to any one of the preceding claims.  12. The elevator apparatus according to claim 11, wherein the hoist is provided at the weight mounting portion.